key and power

hey guys,

ive got two problems with my 2001 y reg 1.2 16v clio at the mo that u might be able to help with

1). THe battery has run out in the remote locker on the key. please tell me i can change this and i dont have to go to ripoff renault. if i can, how the hell is it done and what do i need?
2). I think theres a problem with the accelerator cable, cos when i try to fire up the beast sometimes she doesnt start, and i think that fuel isnt goin into the engine, is this a problem anyones come up against before? this problem is fairly new, and it seems to be very erratic...

any thoughts?

andy