The idle temp is good, load a bit high.
i have the same cooler as you and my rig is a 965 OD to 3.8Ghz
If you wanted to add a 2nd fan to the cooler, get one with a molex on it and fit that. i have the no spare fan headers either. The fan will run full speed. Get a good quality one so the noise level is low.
You case can take 3 more fans so i would add them, again with molex connectors. As above, get good quality ones that will keep the noise levels down. Ensure that the air flow goes from the front to the back and keep the wires inside the case tidy so it doesnt restrict the air flow.
Also get a can of Pressurised Air and clean you case out, cooler and GPU as well. Dust is bad for blocking flow and incresing temps.
If all goes well, your idle temp might go down 1 or 2 deg but your load will frop 4 or 5.
As an example, my rig idle is 30deg running prime just hits 51deg on full load. Playing Skyrim hits 42deg.
Hope that helps