From what I've read, try a NON-ACETONE nail polish remover.
Pour some on to saturate the carpet in the area of the stain, and blot with a clean towel or paper towel. Alternate blotting and gently rubbing, starting every once in a while with a clean towel so as not to smear the stain around.
Once you've removed most of the stain with the polish remover, you can use Goo Gone to remove the remainder of the stain.
ETA: Upon further reading, nevermind on the polish remover. Most say that the best ever fix for nail polish on the carpet is Windex. Do it the same way. Douse the stain with Windex (the blue stuff), and blot/rub clean with clean towels.
Also, depending on the color of your carpet, you can substitute a solution of hot water, dish detergent, and a tiny bit of bleach instead of the GooGone.
Good luck!!