I agree with amuffin's decision. But if you are still willing to wait, why not check out what AMD and Nvidia are cooking up. The new cards may give better performance (ex. HD7970 vs HD6970). But for your budget you could get a HD6970 or GTX570 but your PSU may not be able to handle it. Overall for me its a toss up between a 560Ti and HD 6950 (either 1GB or 2GB).
May I know what resolution you are gaming at?
The 560 Ti and HD 6950 (1GB or 2GB) can easily handle high graphic settings up to 1920x1200