Welcome to Tom's Hardware Forums,
The very first thing you'll want to do is ditch the stock CPU cooler and replace it with something a bit better - you'll be creating a lot more heat than the stock HSF can get rid of. Pretty much the standard for an aftermarket HSF is the CoolerMaster Hyper 212 EVO due to it's value (low cost, very effective) but it is a large HSF which may not fit your case.
While you are waiting for a new HSF to arrive, read up on overclocking your CPU, see what others have attained at what settings (be aware you may not be able to get the same performance from your CPU as someone else) this should give you a good start http://www.overclockers.com/forums/showthread.php?t=688... and ask questions if something isn't clear
Hope it helps