Any recommendations for a new phsyx card?

I've got a Nvidia 8800 GTX graphics card installed in my computer, and while it does good and all, I think it needs a little extra help when it comes to the phsyx settings. As a result I was wondering if anyone knew of any decent brands of physx cards I might want to purchase. Since I'm a big gamer and all I wouldn't mind if the card costed a little.

Also, while I'm aware that Physx is built into the graphics card already installed, I just wanted to put something else into my computer to help give the current card a little extra support.