Rights in a immovable property (house) for a son -reg

Sir, I am satish aged 44yrs, bangalorean. My late mother had applied for a house through department and was allotted a house(property-A) in Karnataka housing board in 1975. she had paid the cost of house allotted for a period of 15yrs meanwhile we renovated the house by the savings and loan by my parents. later in 1984 my father sold properties in our native village ( a house & lands )which he inherited after death of my grand father and with this money he had applied for a Site (Property-B) through department and he was allotted a site by Bangalore development authority in 1985 and both my parents contributed for construction of house (HDFC loan by my father through salary- My mother contributed from her savings and loans from friends). everything was fine until my mother died inestate in 2002 after a prolonged illness. My father told he had to sell the Property-B or mortgage it for the medical expenses of my mother but actually most of the cost of the medical expenses were reimbursed by State government. My father told he had sold the property to the tenant of the Property-B tenant. I got a job on compensatory grounds and had to work in different parts of the state. my father married at the age of 76 and transffered the property(property-B) to my sister as gift which i was unaware of the property which i thought it was sold, i came to know about this transfer when my father accidentally told this to me. and now he is not allowing me to enter the house i.e Property-A. What are my rights in property A &B please let me know sir and help me to seek justice. I have one daughter(11 yrs) what about her future.