You might as well just get the cpu first then. You'll probably need a bios update on that motherboard BEFORE you put the new cpu in.
You gonna want to go with a model that's at least 3ghz. Athlon II is ok, but I would just go right for a Phenom II 955. That's the best performance for the money and it will run 3.8-4ghz with an aftermarket cooler. Chances are that will be the last upgrade on that motherboard before you have to get a new platform, might as well go for the Phenom II now. $139.
Yea your right. My BIOS is bang up to date. Ill still get the GPU for now. The Athlon II is the only one i can afford for now but it will do in this system for the next year or so. I am designing my own case at the moment, I'm a graphic designer by trade, so Illustrator is my main program. I want to go SandyBridge next year, I'm just waiting for the prices to drop. Going water cooling also. I think I'm going to get the CoolerMaster HAF-X Full Tower Case and modify it. Re-spray it and go GTX570 SLI or 6950 2GB and do the hack on it to make it into the 6970 and run them CrossFire.