Generally you do not use a magnetic pickup with an acoustic guitar but a pickup designed for acoustic's(such as a piezoelectric).
You can use a microphone or a clip on mic/pickup that clips onto the guitar(headstock or sits in the hole). I wouldn't use a magnetic pickup because it won't pickup a lot of the acoustical sound that makes an acoustic guitar sound the way it does(even piezo's are not the best for this).
Generally the way acoustic guitars are recorded in the studio is to use microphones. There are various ways to position the mic but this is generally the way to go if you want to "record".
As far as the laptop thing is concerned. The main issue you will have is impedance matching. What this means is, basically, your signal may be too quite and require too much amplification to recover it's sound which also amplifies the noise. This shouldn't really be a problem though and piezo's and mic's are not as susceptible to electromagnetic noise as magnetic pickups.
If I were you I'd look into getting a mic or a piezo rather than use a magnetic pickup.