I'm kinda confused...did this nut come to your house? If she does not have your home address i would be less concerned. Although i guess it would be easy for her to find that out now days. IMO i would meet her at the vet to show that you have done everything to resolve the situation(in case nut job decides to sue you) I would definitely consult the police to go with you to vet (they will do it) cause who knows what some unstable,worked up stranger might do!!! Be careful!!!