You know what. They say that we teach them how we want to be treated. I agree that calling the police is time consuming and aggrevating but if you were consistant with it there will come a time when he will stop the unacceptable behavior.
Get a restraining order and keep him from your work or get one of the non harrassment orders again.
I know its a pain in the bum... but so will be loosing your job not to mention the senerity you lose at this hands.