Division of room/ mental disturbance

My father in law passed away without any will. He took VRS in 2002 and from 2007 my Husband has been taking care of his parents.My sister in law has been staying with us since her marriage and has never contributed in any expenses or maintenance of the house. Now based of % share she wants 2 rooms, 1 toilet and I kitchen. My Husband, mother in law and my 2 son are left with 2 rooms with 1 toilet and the kitchen needs to be set up. It is financially not possible for us to invest on building a new kitchen or so. When we asked her to set a kitchen she denied by saying that she wants to stay in ground floor and want to access the kitchen(the kitchen was renovated by my husband). She also went to police station and made false allegation on my husband that we are not allowing her to use the kitchen/harassing her. Infact now a days she in knowingly creating a mess in the kitchen and I am cleaning it. I am mentally ver disturbed and thinking about my 2 son who are 4 yrs and 1 yr respectively. It is becoming very difficult for me to stay in this environment.