You should have no problems running that system on that PSU, but why not get an i5 3570k instead of that cpu, that is if you plan on gaming? Anyway the PSU will be fine, you are likely to use under 400watts anyways. The graphic card is great, you might want to take a look at a gtx670, if you don't plan on overclocking and unleashing the full power of the hd7950.
Hope this helps!
I decided to go AMD as Im always on a budget haha. I will probably end up over clocking down the line whenever the system starts to feel "sluggish" but (hopefully) thats a long ways away. I was going to do a GTX 660 ti and i5 2500k (Motherboard is old) but the price difference won me over =P Thanks for the fast reply!