You likely have a desktop.
If not, you could build one with the Semrpon 140. If it doesn't unlock the extra core, that's ok, just play with single core. Or buy the Athlon II X2 240. Combine it with an HD4670, and you've got a 720p gaming computer. The 4670 can almost do 1080p on a lot of games (average framerate is 30fps with everything cranked right up).
(Canadian prices, divide by two for US prices) The motherboard and CPU will likely cost something like $130-$150, RAM is maybe another $40-$80, a good case like the NSK4480 can be had for like $80, depending on your needs a hard drive is typically like $70 if you want a 640GB Caviar Black, and monitors go on sale a lot for like $90 (18.5", 1366x768, good brand names too). Toss in $60 for that HD4670. So you're looking at about $500 for a better experience.
Assuming these crooks want $20/mo or something equally outrageous, it pretty much pays itself off in two years (but the difference is that after that likely only your video card needs an upgrade). Yeah, games will cost you money. But you can always find good games for $20 on boxing day, and this way you have a fully functioning computer.