Honestly, I would sit down with her and your husband and kindly explain why she is making you miserable. If that doesn't work, if you can get your husband to agree, give her an ultimatum: "Stop doing this, this and this or you need to find somewhere else to stay." She doesn't own the place, she is an uninvited guest and you are not her servant.

I'm usually the type of person who will let people walk all over me, but I don't think I could handle her for long without saying something.

I hope you can work things out, a month is a long time to deal with that.