Gift deed

My father and mother got married in the year 1982 and both are govt employees. In the year 1996 they constructed a house and in 1998 purchased an open plot which were (both) registered on my mother's name but later in the year 2001 my parents divided and both of them got married to another persons later in 2003(father) and 2005(mother). At the time of they agreed to divide (in 2001 divorce not given by court) my father asked my mother to register the constructed house as gift deed (since both plot and house are registered on my mothers name) and my mother registered it as per his demand when we (me and my sister) were minors (now we are majors) and later my mother sold the open plot due to financial problems and we both (me and my sister) are staying with my mother from 2001 and my father has not given any maintenance to us. After second marriage my father has three children excluding we both. Now do we both (me and my sister) have any right on that gift deed registered house given by my mother if so what is the procedure to claim it and my father has two acres of agriculture land which belongs to my grand father (passed away long back without giving any will) do we have right on this land when my father is alive?? Thanks in advance.