You're not going to want to read this, jeremy, but the unfortunate fact is there's nearly nothing you can do to increase your video performance. Your MBP is still a great computer I'm sure, but old by mobile gaming standards, and its GPU wasn't that strong even at release. I have a Dell of similar vintage with a GPU one tier lower (the x1300), and I would never dream of trying to run Starcraft 2 on it. The game doesn't even run that well on my Penyryn MBP with its 8600GT GPU - medium settings at best. And it's not only impractical to replace the video card on a MBP, it's impossible since the card isn't a separate card, it's a part of the logic board.
My brother and I built an i7 PC with a beefy graphics card in part so that our gaming wouldn't be limited. See my lounge thread for more details.