Abusive Mother in law.

My husband has not been close to his mother in the years we've been together. He's never had a father. My mother and I are very close. The first time I witnessed the abuse, was the first time we went out to eat with her. She had to pick the restaurant, no biggy whatever. While we were eating she's telling me what an awful child my husband was since she was a single mother. My husbands beside me silently eating. Out of nowhere she reaches across the table and hits him in the jaw, knocking his fork from his mouth, food going everywhere. She laughs and says," his bad attitude at 12 made a good man leave her and go back to his wife." I kid you not! My husband won't look up like a dog beaten and I exploded. "You're blaming him for your married boyfriend leaving you based on his behavior as a child?!" (I was so mad). Her eyes bugged out, clearly shocked by me yelling in a restaurant. The dinner quickly ended. 3 days later my husband's aunt calls demanding to know why I was rude and "cussed her out in public". My husband defended me and his aunt pointed out that his mother was fragile after his father abandoned her, when he was 2. A year passes we don't have contact with her (thankfully). My mom doesn't understand the situation and wants us to "be the bigger person and reach out to her to have a healthy relationship" for my husband's sake. (Talk about a mistake.) We invite her over for lunch. She arrives an hour late, no explanation. My husband visibly shuts down again like at the restaurant a year before. His mom ask us a million questions (not too bad). During her visit she notices our cat. (My husband loves animals). She tells ne about the two dogs my husband selfishly brought home as a kid that she HAD to euthanize. "It's too bad the shepherd was still a puppy. But thats how you train kids otherwise they'll make your home Noah's ark." I tell her thats terrible but instead of looking surprised, she spills her drink on me... (Opps my ass). I go to change my shirt and hear her from the hallway whispering, "You're worthless just like your father, pathetic piece of shit. You're the worse mistake I've ever made and now you're trying to embarrass me by marrying this whore. Don't you think I've suffered enough? You don't even..." At that time I barreled back in the room screaming that she had to get the fuck out, I was calling the police. "Yeah right who do you think the cops are going to believe sweetheart?" I think this is the closest I've come to hitting someone. My husband physically pushed his mother out the door, locking it behind her. I was so mad I was ranting/raving. My husband just went into our bedroom and said he needed a nap and wouldn't talk. She's disappeared after that. Fast forward to now, 2 years later. Husband and I are trying to conceive. His mother calls she's in a moving truck. She's rented a house 4 houses down from our since she can't wait to be a grandmother! The look of horror on my husbands face makes me want to beat her ass and hug him while crying. Oh dear lord someone offer guidance, we can't afford to move. ***Update*** Thank you all for the great ideas! The no trespassing sign and door chains are first. I'm going to talk to my husband about a restraining order, which is hard to do since he never wants to talk about her. So far we haven't had a direct issue with her but I know she's probably figuring out a way to cause us problems. As for how she knew we were ttc, we think his cousin told his aunt who told his mom. Thats the only way we can figure. I know my husband has nothing to do with her and his mom has never had a relationship with my mom. I know last year my husbands work had offered him a job 3 hours away, I'm going to bring that up now that the she-devil is close by. Thank you all again for the ideas and encouragement!