APM wall is a myth. I believe day9 or somebody said you can do everything you need to do with around 80 apm. Just playing more to the point of knowing what to do at all times can increase it from 50 to 80 alone.
This more or less hits the point, but let me expand on it.
The basic question I would have is this: do you know lots of things you should be doing at any given point in time but can't get your hands to do it? Or do you simply look back and notice that you've missed things and thought, "Gee, if I was only faster".
If the answer to the first question is yes, then faster hands would help you, but learning to prioritize could mitigate that. In the latter case, APM isn't your primary problem at all, it's awareness.
Work on hotkeys so that the things you know you need to do can be done faster, but if you are late getting your Robo down, late getting warp gate, late taking your 3rd, etc. then focusing on faster hands won't help you, and might actually cause you to miss the things you're *supposed* to be doing.