How to increase our share in the house?

My family and my grandmother have been living in the same house since generations, actually this is my great grandfathers house, when he died he transferred the property to my grandfather leaving behind a will in support of the transfer, when my grandfather died, in 1990, he did the same thing, he transferred it to my father, even though he had 2 daughters, he didn't leave any share behind for them, now, in 2015, my father passes away, leaving us all in messed up situation, the thing is there's a registers that I came to know about, in which it is clearly stated that the house has two owners, my grandmother and my father, and legally she owns a share of 62.5% in the property,(50%+12.5%), the 12.5% as I've been told by the lawyers is hers because being a mother she too has a share in her sons share, but I'm not getting it, me, my mother, and my mother only get a share of 32.5%, moreover she's been influenced by my aunts who are coming in day in and day out to instigate her in order to seek their share in the property which they'd eventually get from my grandmother. Also my father was the one who has been paying my aunts bills, her rent, he was the one who even got her married, and till now also he was doing the same only because my aunts husband wasn't capable enough to make a living for his family. Now my point is that the proportion here is 3:1, how can our law be this blind? Please help me out because my brother(20) and I(21) are still studying, and my mother s not working, how would we make our living? Thanks