Need help changing voltage on MSI P7N Diamond motherboard with q6600?

Well, im trying to overclock my q6600 to 3.4ghz i have gotten to 1333 fsb (3.0 ghz) but need to increase the cpu voltage but my motherboard is not letting me i have disabled all the necessary things it just shows a list voltages with [AUTO] in grey next to them, can someone help me?