The cpu temp is fine, the gpu is high...
littlefrankus and AlienRod are both correct, I'd take the back off, remove the vid card heatsink(s) being careful not to damage the pads on the memory chips, then clean the gpu chip and re-apply thermal grease. I recommend Arctic Silver 5. Also put it on the SLI chipset when you're there. It's all in the tutorial littlefrankus linked.
Re-use the pads on the memory, I don't know where you'd fine them, but they can be re-used as the memory doesn't get all that hot, the chip itself is the important part for heat.
The cpu gets it's air from the vent on the left side of the case, and blows out the back. The vid card gets it's cooling from the bottom of the case and blows out the back.
While it's open, clean the fans and radiators as best you can with canned air and q-tips.
My cpu idles around 66 deg, and doesn't get over 84 under full load. My gpu's idle in the low 70's, and get into the mid 80's under load. The gpu shouldn't go over 90 deg. I think it's near there that the system starts to shut itself down by slowing down, then shutting off to prevent heat failure of components.