everything aside change the mobo to FM2 socket, the MSI I linked is probably best choice as it is more recent and will for sure have bios that supports your cpu choice. Also change RAM to 1600 MHz kit, depending on price between 1 4GB stick or 2x2GB sticks get the 2x2GB sticks as dual channel can help immensely at times. to wrap things up, if you are not overclocking I would save $15 and get cheaper model Athlon that I linked and put it towards a faster GPU. The 650 Ti is preferable since the 7790 has had some issues apparently, but performance is more in favor of the 7790 but not by much. Other than that keep everything else the same.
with the 7790 you should expect anywhere from 50-55 fps at 1080p with maxed settings. It also depends on your CPU, 55 is guaranteed with an intel i3 or better. so it could fluctuate but I would say 50-55 for sure. the 7770 with an intel CPU would be about 39. So anywhere from 34-39 for sure with the 7770.
Both reviews use a Sandy Bridge-E CPU so they are very powerful, realistically your fps will not be that high, however looking at dates of the article I looked at and the one patrick looked at, there was a 2 month difference. I would say drivers improved performance by about 10fps, you could expect in better performance as of now as well with even newer drivers.