Yea you should def. look into buying more RAM if your only running 512. Id at least upgrade to a gig its not that expensive these days. If you have 2 256 sticks in your computer take one out and put the gig in. Youll have over a gig to operate with! If you get a 2 gig stick it gets pricey. Depends on how much you want to throw in. Honestly I wouldnt worry about more than a gig cause of your processor speed.

Have you done msconfig yet?