Under 500 bucks,look no farther than the Sprinfiel XD 40 S&W,smooth shooting little auto,packs enough punch for most assaliants.

I know this might sound a little sexist but most women won't like the recoil of a full 45 auto,for most comfort look at the 9mm,40 S&W.
As for a revolver 38 special or 32 H&R,but I would go .357 maghunting and .38 special for home protection.
BBJ