Amount In Deceased Father's Bank Account, No Nominees

My deceased father had a savings deposit a/c with a nationalized bank. He did not put any nominee to it. My mother is no more, too. I'm his only son and I have an elder sister. My sister and myself were involved in a legal dispute over property, but this account was left out of the suit schedule due to oversight. The dispute got settled by way of a legally mediated compromise and the civil suit was dissolved. As of date, this account with the bank still lies unsettled. Since the compromise that happened almost 10 years ago, myself and my sister are not on talking terms. Currently I don't know her whereabouts. My questions are: 1. How do I take out the amount from the bank. 2. Possibly bank might seek legal heir certificate, in which case my sister's signature would be mandatory. How can I deal with this situation, given that I don't know where she is currently. 3. Can I ask the bank to settle my portion of the sum. 4. Can I file approach the court seeking part settlement. Thanks