Here is a good comparison between a GTX770 and GTX570. Youd be almost doubling your performance.
As for waiting, dont bother. No matter how long you wait, something newer, shinier, better and cheaper will come out a week after you buy so just buy what you need/want when you nee/want it. If your 570 isnt giving you the performance youre wanting, there is no reason not to buy a new GTX770 or GTX780 or whatever now.
AMD FX 8350 @ 4.815 - 1.40V CnQ enabled
EVGA GTX 670 FTW @ 1070 (1239 boost)
Asus Sabertooth 990FX rev 1
Corsair Vengeance 1600MHz 8GB
Samsung 840 Evo 250GB SSD
Western Digital Blue 1TB x2
EVGA Supernova G2 750
HP 2509B @ 1920x1080
Corsair Carbide 500R
BlackWidow Ultimate & DeathAdder