wait, that CPU will be fine for a while yet, you could go to a 7 series nVidia so save power/heat and get a little more performance over your 470 SLI but it's probably not worth it.
Just wait and save, it will be another year or so when the new consoles are up and running that we see current PC hardware get stretched, unless you are running 2560x1600 and want to run Metro with everything turned on.