Yes. Your motherboard should have a PIC-E 16x slot.
As far as power requirements. AMD recommends a 500W PSU. That is total system requirements. Honestly, if you have a 400 or 450W PSU that is of high quality with maybe 30A available on the 12v rails, you would be ok as long as the rest of your system isn't drawing tons of power. If you are into Overclocking and alot of high end components I'd stick with 500W.