Zalman VF 3000 is also an excellent cooler. Less expensive than the AC. I have it on an OC'd 6850 @ 920/1200 and it stays around 56c under full GPU load with a moderate fan speed (* QUIET!)
If you decide to RMA the card, look at HIS, Gigabyte, XFX and Sapphire cards. They seem to have better coolers. You can also look at tom's VGA charts for ratings on both temperatures and noise for GPUs.