If the fan is an exhaust type which it sounds like it is from your description, then yes the fan should be pulling air from the case and blowing it onto the GPU and exhausting it though the back of your case though the second expansion slot.
Personally I'm a fan of the
Arctic Cooling line as they seem to always fit the board correctly and run extremely quite. From the looks of it they don't have one out for the 7950 line, but the 7900 cooler might fit. I would email them and ask such and if not find out when the plan to have the 7950 version out. They are normally pretty quick in getting new designs out.
Jam it back in, in the dark.