Look up your case type, and look for a VGA bracket. Should hold your GPU. My HAF X came with one, but I don't use it. I really don't think a 7950 could be enough to put pressure on the slot, have you made sure wires are not pulling it down?
I had a 690 in my system once, with the same board as yours (I had it in my system for a couple of minutes to check if it works with my friends computer, didn't work in his system), and it didn't bend at all. Very Strange.