Hindu father sold land without 1 wife's consent out of 2 what to do

My father having two wifes, and each wife are having two sons. I am a son of first wife. There was 3 acres agriculture land on my father' name ,he is staying with second wife and her sons. My father has sold the land without our knowledge and my mother' s knowledge. Second wife and her sons and my father have planned and sold. Then how can we get money or that property. What will be the % of share of ours. Please guide me. We are Hindu family.