I'm in the same boat, I just need to upgrade one part and I'll be back in the game. My CPU is letting me down, an old S939 AMD X2 4800+. Trouble is I need a new motherboard cause S939 phased out years ago.
Nothing much runs Crysis well. If the game loads and doesnt CTD, you have a decent computer. :P
The greatest delight is to mark one's enemy, prepare everything, avenge oneself thoroughly, and then go to sleep.