Pram Replacement

Hi Guys & Gals :)

Well I'm new to Mac's by about 3-4 months. I work on Pc's and know them inside out but Mac is a different story! I bought a powerbook G4 17", 1.67 processor, A1107, Low res' which I must say is a very very nice laptop.

The main battery needs replacing and tonight when I booted up the date came up which on any laptop is the Cmos/Pram battery. After checking out the Pram battery I'm wondering if I can buy just the battery or do I have to buy the complete assembly of the Pram/USB board?? Where would I get one from???

Can I get the Pram/USB board out without having to pull the whole computer apart and is there a video showing how to get it out???

Many Thanks

Annie :))