Ok that sounds rather bad. Failing and it took a month to get the full refund I would rather go with a reliable GPU :S
Problem is some manufacturers require you to send the items abroad, sending to Ocuk the postage is not that bad, and they can test the item to confirm it is faulty, then send the item onto the manufacturer for replacement, I think mine took a bit longer manly due to the fact the 4870x2 was end of line.
But Asus have put a week turn around in place for there motherboards and the 3 years sounds good.
Hopefully you wont have the bad luck I had on my system.