I am very happy to read bass and treble individually. I can also play them individually very well. I tend to learn a piece(small to medium size and easy to medium with a hard one thrown in now and then) But when I try to put them together, it's almost back to square one, I can barely do it.
Am I going about this the wrong way? Should I read/learn a few bars individually then put these few bars together and so on? Any insight from experienced pianist would be appreciated.
Sure, working on a short section can help. But most of all, make sure you can play the separate hands slowly WITH NO FUMBLES. Preferably with a metronome click. Then start putting it together, even more slowly.
It's not clear if your problem is reading two staves at the same time, or playing independently with both hands.
You can certainly practise the "playing" problem without the complication of sight-reading at the same time. Find some short exercises with different rhythms in each hand that you can memorize.
Learning to do several different things simultaneously takes time and effort. Even a very good piano student can expect to keep facing harder challenges over a time scale of many years - right up to "professional pianist" level.
