Bottom line is, if your computer can't handle the game as it is now, it may be time to consider an upgrade. Hardware stats are pretty much fixed unless you get into overclocking, and even then, the benefits from that are usually marginal at best (+2~10% system speed while stable?).
It may be more worthwhile to get a completely new computer if your current is more than say, 6~7 years old... trying to upgrade a 1998 Compaq or better usually doesn't end well.