You can build one for 500 to play CS source.
My athlon 2600 and 9600pro plays it well.
What kind of comp do you have now. Maybe you can upgrade it.
Also, I would go nuts playing FPS mutiplayer on Dail-up. Tried it with Quake II and never again.
Sattilite has alot of latancy, it has to travel a log distance. If you get cable on your area get that.