Look for places there are still clearing out their old 7000s series, the new AMD R9 280 is just re-branded 7970, and any of the "old 7970s" under 300 (perferably around 250) is a great purchase. On the CPU side 3570k is still a great CPU once OCed (I'm assuming you already have)
Edit: Also take upcoming software into account, G-Sync and streaming looks really nice, even though AMD is starting to beat nVidea in performance, nVidea's streaming feature could be really cool to use for tf2 without the need for a good CPU. G-sync will be an absolute beast if you have the supported monitor (even running at 30fps it wouldn't look terrible). The price drop of the 770s is great too. Encourage you to do more research (on actual hardware/techwebsites) before purchasing; you could even wait for the Christmas (Black Friday?) deals if you want.