Hey Community,
Need some help, I was given an old Dell Box XPS 400 which was running Windows XP at no cost.

Naturally I wiped the drive and installed Ubuntu 12.04 64bit on it and its running like a champ.

This Dell XPS 400 has the following Specs:

Processor: Intel® Pentium(R) D CPU 3.00GHz × 2
Ram: 4GB Ram
Video Card: Nvidia GeForce 7300 LE (512MB) /PCIe/SSE2
Hard Drive 250

I wanted to run Linux Steam Beta, League of Legends and Dota 2 (via Wine) long story I've discovered I need a better graphics card.

Without spending any money on upgrading the current PSU which is 375W I would like to find the best graphics card suitable for this box. I would like to stay with Nvidia so I would appreciate any suggestions on what card I should get.

I'm not planning on spending over $100 which I know its not worth it since this rig is a bit old..... but I just got a $30 gift card to best buy so I can use that to fund the card a bit