SSD will help in Loading times, RAM will help in performance. But really most of the game is depending on CPU and GPU, which it doesn't really sound like your lacking in with that i7 and 330M.
Yeah that's what I thought too. I plan to reload OSX over Xmas from scratch and may get Windows 7 too, see how it goes from then. I could fancy a quad core i7 iMac but then I loose portability, well lying around the house anyway.
Trouble is I'm winging away but I had to totally restore my OSX partition after I, cough ahem, kinda deleted it installing bootcamp haha!! So I THINK I may be getting a performance hit cause of this.