I'd say stalk her, and start digging up dirt on her.
Either that, or just say, "You're a childless mother that can't relate to anyone therefore you'll never have a boyfriend because you're such a crazy bitch. Quit taking out your anger on yourself on me. I'm not going to step up to your level of insanity. Now, get the forget out of here before I call the cops crying, 'There's a creepy lady stalking me, and I think she wants to drug and rape me!'."