Legal Heirs

Dear Sir/Madam, I am a Christian and my wife is also a Christian and our place of residence is Chennai. My wife (age 56) died last month. We had 2 children (1st was daughter and 2nd was son) and both of them died at 11 months and 26 years respectively. . Presently I have no children. My wife has her aged mother (78 years, alive) who is a state government pensioner, 1 brother (earning and married having 2 daughters) and 2 younger sisters who are married (one is employed having no child and the other one is a housewife with 1 daughter) living with their respective husbands. My wife's father has died. Both the sisters, the brother and their spouses are alive. Kindly clarify who will be my wife's legal heirs for the landed property in her name bought from my income and life insurance policies with nominee in my name for which I was paying the premium. My wife was a housewife throughout her life without any independent source of income and she was financially dependent on me. Look forward to receiving your valuable opinion. Presently I am in Bangalore as I was recently transferred.