What will be my share in my fathers property if Fathers property.

Dear All My Father had two wives. And he Died on 17/10/2006 My Real Mother was married to my father before independence. We are four sisters from my mother. and i am the second. Say A, B, C, D. And I am B. My Real Mother died 0n 2/4/2005 before HSA 2005. All the sisters were married before 1975. My Step mother got Married to My father on 28/01/1978. We were all married before this marriage. we have 2 brothers and 3 sisters from my step mother. They all are adults now. My father had purchased properties in the name of my step brothers(at the time when they were minors) and got registered in their name which is today in their name only and in their possession. And he left with a land in his name without any will and that was self acquired. I want to ask that whether i can claim land belonging to my brothers as they were not earning that time and the land was purchased from the funds earned my by my father. Secondly what will be the share i could claim from the property in name of my father and what will be the share in the property which is in my brothers name. I asked a local lawyer the same question but he said that as your mother was the first wife therefore she and you all loose all your rights to property as My mother is no more wife to my father. But she never get divorced and she used to live together with my step mother and her children. Is he right. Thanking You