I wouldn't limit this to limbs (+voice) only. Another option is to use hand fingers, or even sections of body extremities. For instance, one part could be "played" by the base of the palm and the other with the fingers, or using external/internal parts of the hands (by rotating the wrist in case of alternation).

Also consider that asking for generic tips based on such vague questions is rarely a good idea, and we normally avoid answering such questions, also considering the involved responsibilities: it's your voice and your body, giving a (possibly) bad advice could result in seriously damaging them, possibly permanently. That said, as written above, your description is completely insufficient to help you in any effective way. You may consider providing samples of your voice and attempts, but be aware that, as said, we may choose to avoid any suggestion we could be accounted for to begin with.

Hello and welcome to Music, Practice & Theory! Please take your time to follow the tour and read How to Ask. Be aware that this is not a tutorial website, and while we generally answer to questions asked by individuals, its purpose is also to mostly provide a common knowledge that would be helpful to anybody. Right now you're asking a quite "personal" and vague question: we know almost nothing about your physical and musical background, and your description is a bit obscure (it almost seems like you can only sing two notes, which is quite odd), and then it's hard to help you in any way.

@Tim And that doesn't even consider search query aspects; let's assume that Van Halen was the actual performer (even though he wasn't, as per Todd's note) and nobody ever wrote the full name in comments or in a possible answer: a user may have searched a related query using "[Eddie ]Van Halen" instead of "EVH" for a similar question, and this post could have been possibly shown with a low score (possibly, many pages after the first results). Such usage of uncommon abbreviations isn't helpful to anybody; the fact that we (as frequent users) could eventually look them up is irrelevant.

@Tim I get your point. Still, even though I'm a common user of this site and familiar with many musical genres (and I do know about Van Halen), I didn't get the EVH reference. We're not talking about a relatively common abbreviation or net slang within a phrase, nor (more importantly) a technical musical abbreviation that almost anybody here would know (eg: "pp" or "dc") because it's part of general music practice and theory, but a fundamental aspect of the question for which even somebody not well versed in specific guitar techniques or amplification may provide help.

@Tim I agree, and anybody could Goggle it like with any other abbreviation, including more common ones. Yet, Google can give very different results depending on the user search history; it may not be this case, but I don't really see the point of abbreviating a person's name.

Then please edit your post and remove Eddie Van Halen references in the title/body. Also avoid such terms in future posts: "EVH" is not a common abbreviation, the fact that people very familiar with the song and its background may understand it is irrelevant. Also, MP&T is not a tutorial website: we don't generally provide "guides" on how to get a specific sound based on "how to do xyz" posts: did you actually try to get it? What did you get? Providing recordings of your attempts would be much more helpful to properly guide you in understanding why you didn't get it and help you with it.

I believe it's theoretically simpler (and conceptually more adequate) to divide 60 by the tempo and then multiplying by the relative fraction: 60 / 108.173 * (note duration) / (beat length)

What do you mean by "piano autoplayer"? What are you going to "play", MIDI files or anything else? I sincerely doubt that you would only need eighth values. In any case, the formula is relatively simple: the tempo is based on the meter, if it's a simple meter (eg: x/4), then you get the duration of each "beat" (a quarter) dividing 60 seconds by the tempo (eg: if it's 120, each quarter beats lasts 0.5 seconds), therefore eighth notes last half that time. But, as said, if you're "making" a player, it's quite likely you'll get quite different durations and tempo markings.

» effective way to know about many aspects (and your current limits, and I'm not just talking about physical ones), so nobody tells you shouldn't even try to begin with. But, you got a teacher: talk to them, ask about the challenges it would present, both for any fully trained pianist and for your current capabilities. But also try to consider the "hidden" difficulties mentioned above, as it's common in early learning stages to overestimate our own capabilities, like "I learn pretty fast": which may be true, but you'll probably soon find out that it's not "as fast" as you initially thought.

Adding to what Andy wrote above, a (good) teacher is also able to know the "hidden" difficulties in a piece. Being able to reach a 10th is only one of the many aspects and challenges that must be addressed when facing a new piece, especially if you're a beginner (even relatively speaking). Consider some metaphors: does being more than 6ft tall and knowing how to play basketball suffice to make you a fully qualified NBA candidate? Would it be enough to own and drive a 200 MPH car to make you a Formula One driver? This doesn't mean that you shouldn't try and learn, it would certainly be an »

@user1079505 You're right. Yet, we have to consider two important aspects. 1. that date reference may be considered as possibly biased: when the OP arguably states (remembers?) that they noticed the difference; unless they are able to provide accurate and consistent records of their capabilities, it's an assumption, especially considering their school business (for what we know, that degradation may have started many months before as well). 2. body changes in adolescence can be huge: even a couple of months of missing physical practice at that age can be virtually likened to years.

@JohnBelzaguy There are cases for which only relying on symbols because they're standard is actually a complication. For instance, the attempt from the OP is quite ambiguous (despite the fact that it misses the point in which it should go to the coda) as it's unclear when one should go to the first or second segno. The suggestion from Aaron is more appropriate, but, in theory, different endings/voltas should only be used when the musical contents actually differ, not just to "help" the structure.

@JohnBelzaguy It certainly is open to personal preferences, but with a structure like this using symbols only can be confusing. The player doesn't have to continuously jump to the explanation: if they're experienced enough, they will be able to understand and memorize it in a few seconds. It's not "standard notation" because it doesn't exclusively use musical symbols, but considering the possibly modern musical setting of the piece, text explanations are common in arrangements; even the Real Book contains some relatively complex details (eg. "Seven Steps to Heaven").