How long is she expecting to stay with you OP? It's a long way to come so assume at least 2 weeks?
Firstly, you don't have to suck it up. As other poster have said, this is a conversation you need to have with your DH to find alternative places she can stay. Even if you didn't have anxiety, having a person to stay for several weeks is an imposition. That is not preventing him seeing her as he still do that if she stays nearby. You need to sit him down and calmly explain what you need from him and ask for his support and ideas for alternative accommodation for her.
If you really can't avoid her staying, then you asked for coping mechanisms. The first is getting your husband to agree exactly what he will do in this time to manage her. Such as taking leave to be around to 'entertain' her and support you.
I'd start by agreeing 'house rules' with your husband and he emails her those in advance. Something along the lines of "last time was difficult for us all and we don't want this visit to be the same. We now we have Baby as well, which changes things a lot, so this time we'd like to set out what the expectations are so this visit goes more smoothly. Such as ." (... asking before inviting people over, treating Weasily with respect so no unkind comments, asking before taking over the kitchen to prepare meals, her spending time outside the house every day to give you time alone with baby etc).
Once here, don't fall into the trap of being waiting on them hand and foot, he does that. She eats your meals, or uses the kitchen after you are finished or buys a takeaway. I know you are finding leaving the house hard but could you take baby and stay with family or friends for a few days? Or have friends visit you for coffee when MiL is there for moral support. Just find ways to avoid her. Call her out firmly on unacceptable behaviour and walk away/out of the room if she is rude.
It may be hard, but stick up fr yourself assertively and don't let her 'take over' in your own home.