With two cards, if you're getting a lot of heat from the PS and no heat from the other exhaust fan then the heat you're feeling coming out of the PS could actually be FROM the PS.
Do you know the quality of the PS? Is it a "cheapie" or something more premium? I ask because cheap power supplies have pretty sucky efficiency ratings, so the more power your system needs to more heat your PS generates. It you're using a budget PS I'd definitely consider upgrading to a more premium PS with dual fans and/or "80 PLUS Certified" at least (80 PLUS Gold/Platinum is better, but more expensive).
The heat is coming out of both fans because there's a lot of heat built up in the case from the GPUs.
The PSU is a new GX 650w from cooler master. Not the best quality but it's never usually hot so I assume the heat is just heat from the GPUs. I believe that PSU is 80+ Bronze certified. Is that any good? I was on a bit of a budget. I don't want to spend a year paying off my rig so I didn't really want to spend a lot of money.
EDIT: Although I really want to buy another GPU but I feel uneasy about whether i'll be able to pay it off or not.