Powermac g4 Quicksilver PS upgrade

Hi, I'm a first time poster and first time mac user, so I'm having a little difficulty with my mac. I bought a powermac g4 quicksilver on ebay a couple months ago, and I've done numerous upgrades to it.

Specs:
1.5ghz processor
1.5gb ram
GeForce2 MX

So I feel that it's in need of a serious graphic card update, so I bought a radeon 9800 off ebay for really cheap. But when I installed it, my computer wouldn't turn on. I soon learned that my power supply couldn't handle it, so now I want to upgrade my power supply. Being a long time PC user, and comfortable with opening up the case and all, the actual upgrading shouldn't be a problem, but I'm having trouble finding the right power supply. The radeon 9800 needs at least 300W of power but I've looked on a couple sites and they don't come cheap. I was wondering where I could find a cheap power supply. Is it possible to use an ATX power supply? Also, I found a decent priced one (around $100) on ebay but its for Digital Audio, will it work on my quicksilver? Thanks in advance.

-RAWR

That particular model should have a 340Watt PS, have you checked? The Digital Audio PS would't work, different PS.

Oooh, i figured it out... I made a stupid mistake! Thanks for the help, btw.