I don’t know what to do please help

Basically I’ve been with my SO for 12 years, we moved in with his grandma since she was going to lose her home. All she has is her social security checks that aren’t even enough to pay the mortgage. She has a really nice home with large property which was perfect for my husband and his work. Before we moved in she actually asked all her children 4 of them( all adults now) if someone would pay her bills so she doesn’t loose her house she will leave the house to them. All of them said no so she turned to the grandchildren and we said yes since it seemed like a win win for everyone. We have been paying all the bills for 5 years now. It’s a 5 bedroom house we have one bedroom and the garage and she has the rest. She has all the bedrooms full of junk and the living room full of junk it wasn’t like this when we first moved it she but became this way. We finally told her we will need to clear out the living room we will buy nice couches a tv everything and make it nice and a bedroom for a the baby we are currently TTC. We are 28 years old and she is refusing to clear anything out saying we have the garage. The garage is my husbands work space it’s dirty and full of tools. We can not raise a baby in these conditions she has created here. Now we feel like she has been just using us to pay her bills but doesn’t at all see this as a shared home. I’m frustrated and don’t know what to do.