Hi Ravi, answer to your question is as follows :
1. Yes, you need to file an FIR ASAP. This needs to be done in Pune preferably.
2. It is a good idea to give a public notice in 2 newspapers - one English and one vernacular. This will serve as additional proof of the loss of your sale deed.
3. Apply for a certified copy of sale deed. You can do this at the sub-registrar office where you had originally registered your property. Once you get the certified copy of sale deed, you can consider your problem solved.