H.S.
I remember the first time you posted about your hubby's grandma. I was rather horrified about some of the things she's pulled yet no one has interceded on your behalf. This is clearly something you must discuss with your husband.
I have a love/hate relationship with my mother. She can be quite cruel to our respective spouses. She unfortunately learned this behavior from my late dad and believe this to be acceptable behavior. She is also a person who will manipulate anything that you say to her. I've kicked my mom out of my house for disrepecting my husband and the rules of my house.
This is something you will need to communicate with your husband. You need the support of your husband for this, if he allows this behavior to continue that is more or less indicating to his grandma that it is ok to treat you like this. When my mom first moved in with us, i tried to talk to her about what the expectations were - me and hubby were the parents of the kids and that this was our house...instead she acted as if she were the queen and made life miserable for my hubby. So needless to say, she got the boot when i got frustrated with her inability to listen.
My mom has gotten a little bit better, but i've had to tell her to drop some topics if she wanted to keep the peace with me.