Monster MIL

My MIL is here staying with my husband and I till after Christmas. We currently live in her old home since she moved out of state a few years ago and my FIL passed away a year ago. She has decided she wants to move back at the end of next summer. So my husband and I are going to look into getting a mortgage for a home of our own. She told us today though that she want us to replcae the roof of the house and deck before she moves back though and wants the back yard looking the way it was when she left. That is not up to us though! I refuse for my husband and I to fork over all that money to fix her home she is taking back when we need that money for our own home! It was not us that ruined the roof or deck, the weather and it being built poorly did! Also the yard looks like that from my FIL not doing anything to take care of it for a year! We have done work to it to make it better as it is! It took her 5 years to get that yard to look good, how does she expect us to do it in less than 1?!! Oh I am so pissed! I refuse to pay that money to get it fixed! I will have my church come help do the labor like they said they would, but I will not pay for it, she can!!