Q: What is the best Nvidia Graphics card for gamming I can install in my PowerMac G5 In the $200 range

I just got a hand me down Power Mac G5. I want to get a powerful graphics card so I can play games that really need to nice graphics card to run. Preferably one that is in the $200. Im looking online and all I can find is graphics card that are made for running Photoshop and Final Cut Pro. Also most of then are in the $50 range and i just don't trust that no matter how powerful it says it is. Anyway any recommendations of what I should get? I want an Nvidia?