I don't believe we have any modified drivers for this. However if your wanting to push it to the max a little more, you can try NiBiTor.
This program will allow you to over clock the gpu alot higher that normal through increasing the gpu voltage. Though please note, increase that very cautiously as the higher it goes it will create alot more heat then normal.
This is done by flashing the bios on the gpu. Once you get the voltage up you can normally increase the overclock further then what you could before.