Just a suggestion, I know it's above your budget and I don't include keyboard/speakers/mouse. But spending just a little more it's way more worth it. Mainly because you get that 7970.
7970 vs 570 http://www.anandtech.com/bench/Product/508?vs=518
It's so much better but I did have to cut back on other things, but overall I think this build would be better.