Well, let me say right off the bat, I've never done this before so please forgive my stupidity.
Your temperature is not an issue, but your motherboard is if it doesn't allow for changes to be made to core voltages and the FSB. You can try using a software utility (like SoftFSB or the like) but they depend on motherboard support so you may or may not have any real luck. Also, the software methods of overclocking are generally not nearly as effective as making direct changes to the CMOS. If you decide to scrap the mainboard and get something more friendly to the enthusiast, give a shout and you'll have a LOT of help in getting the most out of it as you can.
Good luck. I haven't kept up with the overclocking utilities, but some have had luck with them.