If the snapped lug nuts are the original aluminum ones, you can purchase a hole saw. Just read up on the second link that John has provided. Just be careful when you get close to the finishing point in shaving off the lug to avoid damaging the wheel. I managed to salvage the wheel as well as the stud by leaving a small portion of the lug nut. I then tugged at the wheel and the lug nut just snapped. Yes, I do use anti-seize all around now
. Good luck!