How do I replace the battery to a car remote?

[JakeXIV]

I have a 1998 GMC Jimmy, and the door's remote control has stopped working, but only after the signal appeared to fade, i.e. I would need to stand closer to the car in order for it to work. How do I open the remote and what battery do I need?

 

[Simon]

Small screwdriver and a trip to radio shack.

 

[chottwo]

take it to a dealership..they have to do it..