Have you heard of Pre-Paid legal? Years ago I used them for about a year to handle some legal issues I was having, and it worked like a charm (at the time I was only paying $16/mo, and it saved me hours of headache). They can send your neighbor a notarized letter on their Attorney letterhead, which may help her to "stay in her lane". The referring attorney office they will give you will be local, so they will know your city code.
Also, if you haven't already searcned on Nolo, there is probably some good verbiage on harassment, cease and desist, interfering with your doing business, etc., and I would photocopy and send her a registered letter with codes, etc., so that she knows you mean business. A bit of work on your end up front, but I have had a nutty neighbor as well. Good luck!!