i don't mean to be condescending or mean in any way, but if you lack the knowledge as to where to source your sound signal, it's quite possibly best left to an installation shop to do that...
typical places (best buy, CC, etc.) usually charge around like $60 or so for it, but if you talk to one of them on the side, they may 'borrow' a drill from work and do it for you for something like $30 (that's what i did for my old car.. you gotta be kinda sly about it though.)
or, check your local forums and see if anyone in your area has experience and wouldn't mind lending you a hand. that's probably the best route to take and your first choice.
