Property Rights

My dad was already married to a lady forcefully. But he was in love with my mother. They went to temple and got married. So my mother is the second wife ( not legally) as they do not have marriage certificate. My father worked in Dubai so he was far from us for about 4 years. He took a flat in Virar before 17 years the flat is on his name. In his will he has clearly written that after my death the flat should be given to my wife Nisha Patil (my mother) . that legal paper has bombay high court stamp and even the lawyer had identified my dad and my dad has signed the paper. Unfortunately he passed away in Dubai. after that his 1st wife was not giving any rights to my mother inspite of that will. I'm his daugher 19 years old. Do i hv any right in my dad's property? Can my mother still get that flat according to his will inspite of not having any marriage certificate of him n her.. I use my dad's name . my dad has even signed on my birth certificate as father. Can I claim my right in his property?