You've got about the same commute time as me!
I'm afraid Radio Shack is not going to be able to help. The unit is glued together pretty tightly. I used a dremmel cutoff wheel to open one up (did this as an experiment in another thread). I'd be afraid of damaging it permanently if it is you only way to start the car.
Pictures here:
http://hoxnet.com/p/FOB
From this thread:
http://www.e90post.com/forums/showthread.php?t=372667