Looking for a decent video card for my optiplex 390.

Like the thread title says, I'm looking for a decent video card for my Optiplex 390 PC. Current specs are:

Processor: Intel(R) Core(TM) i3-2120 CPU @ 3.30 GHz 3.30 GHz
Installed Memory (RAM): 4.00 GB (3.17 GB Usable)
System Type: 32-bit Operating Sytem
Windows Operating System: Windows 7

I'm looking for something under 100 bucks, doesn't need to be TOO graphic intensive, this is by no means a gaming PC, just want something that my girlfriend can use so she can get on SecondLife from my PC. Let me know if you guys have any ideas.