So 500w will be enough to support my build?
A well-designed 500w PSU, definitely. In fact, I'd suggest something like this for your build:Corsair CX 430W 80 PLUS Bronze Certified ATX12V Power Supply
($42.99 @ Newegg Canada)
That'll support GPU's up to a 7850/660 without breaking a sweat, and if you'd care to buy a y adapter, it's +12v rail can support up to a 670 / 7950 if you're not running a large raid array or overlocking your system