She can hit him with a temporary restraining order if this continues. Clearly he seems to be aiming this at her, since he is pulling up to where she is parked, no matter where she is in the lot. She will have to get his name, though. That can probably be obtained via his license plate through a PI, though this will cost a bit of $.

She also might simply want to stop eating lunch in her car for awhile, or drive to another lot to eat. That might be the easiest way out of this one.