Dear Concerned,
On the basis of the Death Certificate of your Father and mother , you need to get the names of all of your siblings mentioned/ updated in the Revenue Records.
YOU might need a Legal Heir Certificate for this which you will be able to get through the Magistrate concerned.
Once the property is on the name of all the Legal Heir, you all will be able to sell the property .
Market value and Circle rate generally differs - you can check the circle rates from the concerned patwari / thesildar office and market rates can be taken from any brokers in the market - to get a valuation certificate appoint a government certified valuation agency to do that.
Best of Luck