Don't get that psu or either one of those mobo.PCPartPicker part list
/ Price breakdown by merchant
/ BenchmarksMotherboard: ASRock H77M Micro ATX LGA1155 Motherboard
($69.99 @ Amazon) Power Supply: XFX 550W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply
($61.24 @ Amazon) Total:
$131.23(Prices include shipping, taxes, and discounts when available.)(Generated by PCPartPicker 2013-04-01 03:26 EDT-0400)
That brand of psu you had sucks and is way too much power for one gpu. The money you save with these changes you might be able to get a gtx 660 ti or hd 7950.