Your CPU looks like the weak link there. You may be able to get enough extra performance out of it to be good enough if you overclock it a little harder. Personally, if it were my machine, I'd put in at least a quad-core or more likely a 1055T hex-core. (Yes, the 1090T is faster and easier to overclock, but if you know what you're doing with overclocking, you can get pretty similar performance out of the 1055T for $100 less).
You don't need more than 4GB of ram, and the 5770 is solid for anything except the biggest monitors (1600 pixels and up). I also think that if you plan on keeping this machine in the long term, you'll be better off with 64-bit Windows 7.