|You just need a new video card. |
I remember running Far Cry ages ago on a 1.4GHz Athlon Tbird, Radeon 9700 Pro, and 512MB of RAM. That setup could max out most of the video settings.
If you have an AGP slot, a Radeon 9600XT would be a great card for your rig.
HTPC | Pentium M @ 2.82GHz, 2MB L2) | 4GB | 1.0TB | Radeon HD5750
Blu-Ray | Win7 Pro | HDMI out to Onkyo TX-SR707