People don't pick a voltage for a frequency when overclocking. That is up to the performance of the silicon in each individual case. The usual procedure for overclocking is, you up the speed of the chip until it fails validation, then up the voltage to stabilize it. If you can't stabilize it at a given speed, you've reached it's limit.
Also, currently you have a low clock speed and low voltage in your CPU. You should find if you do overclock, power use by your CPU is not going to scale linearly, and you will reach a point at which you're requiring high voltage for little gain, dumping large amounts of waste heat. The chip may be great at stock speeds, but until you actually clock the chip up you won't know if it's great at overclocking also.