House property

My Grand Father, written a WILL after one year my marriage, in my and my husbands name a portion of his built house which will take effect after his death. My grand father died in Nov 2011 and grand mother in 2000. My mother deserted my father and living with her paramour in the adjacent house owned by her. After my grand fathers death, I requested her to cooperate to get the property registered on my name in the sub registrar office. After several times request she revealed that the property has been transferred in her name and I have no right. After her death the property goes to her grand son(her son's son). My several attempts to make her understand that the WILL written to me after marriage is a stree dhan. You are being my mother how can you cheat me like this? Her reply is do what ever you can, Your Will is cancelled and now I am the owner of property. my mother and her paramour, and daughter- in -law, and her grand son, planned a conspiracy to eliminate me & my husband from possessing the property, while my grand father was residing in my mother's house while he was old and depended. I request legal Experts and advisors to give me suggestions,to get back my house property (small portion). Thank You,C.Siddeswari.