Power Supply:XFX 650W 80+ Bronze Certified ATX Power Supply ($59.99 @ NCIX US) Total: $59.99 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2014-06-04 19:48 EDT-0400)
Your card uses close to 300w at peak so it would depend on your CPU. 500w for a FX AMD series may not be enough.
I would get a 550w, or a 750w just for being able to do dual cards later as that is the minimum.
Power Supply:XFX 650W 80+ Bronze Certified ATX Power Supply ($59.99 @ NCIX US) Total: $59.99 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2014-06-04 19:48 EDT-0400)
If you GPU is around 300w and your CPU at stock is 84w. Your system without OCing could run off of a 500w PSU. So with OC you will be more than fine with a 650w.
XFX TS Series 750W Single Rail ATX 12V 62A 24PIN ATX Power Supply 80PLUS Gold Certified $70 for another couple hours if you want to go with a 750 Watts from a quality maker