You definitely won't be overclock via the BIOS with that board. That's the only way I'd ever overclock for 24/7 use, but you could try software, such as ClockGen. I don't really recommend it though. You'd need to crack open your case to locate your PLL model on the motherboard, which you would need to manually input into ClockGen, and there's no guarantee that it would work for you.
Read about it there. I'd seriously reccomend just buying a new board if you're interested in overclocking.