hmm, at this time, I would say grab a 2nd hand HD5770/HD5750 level card and save the money(should be 4k or so). It would make sense too, since HD5770 is generations old and the new series isn't as far as people think(heard demonstrations might, "might" be next month).
If you want to buy a new card, HD6850 for around 9k, look no further