Ok.. I've had problems where my Trackpad won't move the mouse correctly when the computer it cold / warming up, but that's because the chassis is warped.
To solve my problem, one person on here recommended I put a penny under the side that was higher in order to stop the wobbling... :-/ I'm not too happy about it, but there's not much I can do. I don't think it's Apple's fault, more the iCurve I used (which
Sorry I can't help much with your problem, and I know this might not help you much in the immediate, but you might want to think of replacing the whole Upper Case of your 12" (check out iFixit and click on Case Components :
http://www.ifixit.com/Categories/Aluminum-12-Inch/53 )
Or go to a local Apple Store and see what they have to say....
Cheers,
Awfers