Yes. Underclock or overclock one of the cards. http://www.guru3d.com/index.php?page=rivatuner

Just out of curiosity, have you tried eBay to see if you can find the same card? A picky person like me would rather have 2 of the same even if it meant replacing a perfectly good card, but that's just me.

Any 260 will work just put the newer one in the first slot and your second card should automatically grab the clocks from it. Won't be much of a difference anyways. Your card should be clocked 576core 1242 shader i think and the 10 mhz bump to the new cards clock won't make any difference. (Newer card in top because with air cooling your card on top will run 8-10c warmer then bottom card and the 216-55nm cards run cooler then your old card.) 

Coolness. Thanks guys. I'm glad I will be able to still use this with the newer ones if need be, though I will try to find the exact card if possible.

I forget about ebay. I'll give that a looksee as well

Great card.  I have the newer version which runs cool and smooth.  Hope you find what you need on eBay because the 260 has gone up a bit in price - at least from the places I checked. 

I see what you mean. I paid 150 for mine at microcenter. It's listed at $160 now.

Yea, They're still pricey at the moment, but hopefully it won't take them long to drop with the 480/470s hitting the street recently.

Just got through reading a review of the 480s and man, it's kinda disappointing. Here six months after ATI's DX11 offerings and they can only come close to matching the 5xxx series in certain games. I could be considered an Nvidia fan, but even I'm not stupid enough to pay almost double for the same performance. Hopefully my 260/260s can carry me past this depressive era for Nvidia.