I'm Dr. Jackie, an interpersonal communication researcher/professor and relationship counselor. And my heart goes out to you for everything you are going through! It sounds like your husband is very wise in seeking out a counselor/therapist. Can I ask if he is still seeing that therapist? If not, I would encourage your husband to do so and also encourage you to either go with him or see a therapist also because you have been bullied and abused and you need to heal and get help like you acknowledged. If you want to talk on the phone or Skype with me, I'll send you the JA form after I finish a response here. Perhaps phone or Skype might make it easier for you to talk about this.
As for what to do, to start, like I said, therapy/counseling is my top recommendation. You are in a battle that is something you should not have to deal with let alone deal with by yourself/with your husband. The emotional damage and wreckage has caused deep wounds that will take time and coping skills to begin to heal.
Second, I 100% agree with the therapist regarding boundaries. I think so far you have acted very wisely and very maturely despite the fact that you have been treated completely oppositely. I might take the phone thing one step farther and discontinue or block (or whatever your carrier may do) the ability to leave messages. That way the temptation is not there to leave any kind of message, positive, neutral or negative. The point in taking away that ability is like I indicated--removing any temptation. The less you truly are able to communicate with them, the better!
Third, since your husband is on your side in that he truly recognizes what his mother has put you and him through, I would suggest you get a restraining order against her. I would talk to the officer or at least precinct you dealt with before since they should have the case notes already on file. I am not a legal expert, but the officer(s) can help you go about petitioning a court or whatever is necessary to get a restraining order or some other legal safeguard in place to prevent her from showing up. The police will also be able to tell you exactly what the protection order can include. That is, definitely you can show from your previous police report and phone records that she is indeed truly harassing you. So they can tell you what your parameters are -- your home for sure and you, your husband, and your daughter for sure. But this kind of order may also include your church and places you frequent--if you work outside the home, your job, your husband's place of employment, etc. Again, since I'm not a legal expert, I don't know all of these details. But the police can help you for sure. That is what they are there for, so please, please utilize this resource and please do follow my suggestions.
I'm not going to promise you that a "piece of paper" will keep your mother-in-law completely away from you. But it's certainly very helpful now and definitely down the road to have this legal document in place. You may want to confide in your minister/clergy person also and your friends at church. I am guessing they know that her intentions in showing up at your place of worship are full only of trying to make your life miserable. It is not gossip for you to talk to these friends and explain you are taking some legal action because you truly are scared for your own mental/emotional well being and of course, the well being of your precious daughter.
I hope this is a place to start. Please do not let another day go by without getting this documented legally. While I definitely would not recommend a lot of family disputes be settled by getting the law involved, your situation is atypical. You are dealing with someone who in my professional opinion (although I have not met her so I can't label this for sure) surely must have some mental and emotional problems and truly needs professional help before she does something that is irreversible. Her threats and words are damaging enough. It would be a tragedy if things escalated to physical violence. And you may or may not know this, but often verbal / emotional abuse DOES escalate to physical at some point.
Again, this should be a good place to start. I'll get my phone and Skype information to you. I do wish you the best in this process. If you can talk to a counselor, please, please do so, the sooner the better. You need help dealing with all of this unfortunate stuff. Please let me know if you want to talk and/or respond in this Q&A/email forum.
Take good care,