Rights about married daughter in her mother's property.

Hello, i am looking for a legal opinion on the rights of married daughter in her mothers property. I had 2 brothers and 1 sister. all are married. my father was died earlier. we three brothers and our family and my mother are lived in a joint family up to my mother's death. we 3 brothers are did joint business in my mother's name and also bought all the property in my mother's name too. Now all the property are in my mother name and business too. but none of them are ancestral property of my mother, its purely owned by we 3 brothers. my mother didn't wrote any will. At the time of my mothers death, my sister took all the property documents without any permission. now with the help of Legal Heir Certificate she changed my mother name in 'Patta' into all our four names, without any notice. Now all Patta are changed in to our 4 names. So, now she told according to daughter property law, i am only having full rights in all the property belongs to my mother's.(in my mother name) And one important thing is, when my mother was alive , i bought one property to my sister, but few year later she written (return) it into my mother name as a settlement and that document is registered in sub-register office. Sir at this situation, whether my sister had no rights?? or equal rights?? or full rights?? in the property that we three bought in my mother's name... Kindly suggest me..now how can we partition..what are my rights. R.N.Arunachalam