Usually you toss in an aftermarket cooler as others have said for overclocking, but with such a slight OC you may be able to obtain it without adjusting voltage to the CPU or very little. So you may be able to get away with using the stock cooler.
I stress test it now and keep track of the temps, if it looks like you got some leeway give it a try with the stock cooler if you feel like it. Just keep in mind of the ambient temperatures because when you have warmer weather like in the summer it can make a huge difference. I know in the winter my room averages 60 or so and will probably hit 95 or so easy in the summer sometimes. It makes my computer run just a tad bit hotter than normal.
First off, get a 7200rpm Hdd,that slow one you have isn't going to help anything,
is your rig triple channel, if not, how is your ram split?
and if you can download and run Cpu-Z for us, let us know the Mobo model and chipset
there may be a software route