The lastest BOS ASUS lists is version 1006.002 which is from 12/1003. If you have used ASUS update in recent years, you probably have the latest BIOS. A BIOS update is not going to change the amount of voltage available to your CPU. A new MB with new voltage regulators would do that.
I know nothing specific about your MB, but have you increase the voltage to your RAM and Northbridege if those adjustments are available. If so, do so with caution in small ncrements and test for stability. Use caution when 'pumping' voltage to your hardware.