I don't think you'll find a factory OC/SC card with that high clocks to be honest, you'll need someone's modded BIOS, but you'll be better off editing the BIOS currently on the card (after you save the original), as at least you know the re-flash won't fudge your card by using your own.
Also, if your clocks are hitting that wall, you probably need more volts, I think the Voltage Regulators with your card allow software mods, you'll have to check.
EVGA Voltage Tuner +Patch might be able to up the voltages (dunno if the patches allow for anything pre-GT200 yet though), otherwise you should be able to up them in the drop-down menu in NiBiTor after making a copy of your BIOS.
Make a copy of it with GPU-Z and see if NiBiTor gives the option of more Volts in your current BIOS, if it does, you can do it that way.
You'll only wanna up the volts a fraction of course, and for long-term stability, you might wanna look into getting a nice MOSFET cooler just to be safe.
Get a second opinion before you set anything in stone though, but view your options in the meantime