I'm sorry you're going through this.
You need a safety plan for each location you'll be at - ie, how do you get into work safely, how do you stay safe at work, how do you leave work safely; how do you get into your condo safely, how do you make sure you're safe inside (she could be in there waiting; she might try to break in), how do you leave home safely, etc...
Alert other people... yes, even if they're older and you'd rather not have them know. It's not your fault that woman is crazy. The more people who know, the better. And the more they know what to do (ie, call 911 immediately if they see her; alert you/your significant other to the danger), even better.
Vary your routine... get to work a bit early sometimes, take different routes (on busy streets, maybe that go by police and/or fire stations) home.
Keep someone with you or go to them. Can you visit a friend for awhile? Good old Aunt Martha, perhaps... especially on Tuesday.
I wouldn't rely on a weapon as your first line of defense. As it's been stated, it could be used against you. It also might give you a false sense of security.
Record every call, every text, every email, knock at the door, etc... and get that information to authorities immediately. As in, the police told her not to call, then she did it three times... you need to call the police back. You're not pestering the police; you're helping save yourself.