I love my 470, but damn, those 570's are making me drool!
I like to have a big fast card, but more importantly to me, is that I can play my favorite games with everything turned up all the way, at 1920x1080, and with never going below 50fps. For me, that means I needed to have a 470 to accomplish that on BFBC2.
I've got the same CPU as you and it's running at 3.5ghz.
Here's a question for the op: do you think I'd see any noticeable benefit jumping from 3.5 to 3.8?