Read this article for GPU recommendations on best bang for the buck. http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-4.html
That mobo will work, but I'd suggest getting an H77 or z77 to work with that Ivy Bridge CPU.
If you're gaming, then I'd up the ram to 8 GB.
The case will be large enough, and PSU is more than enough.