Lease deed

Hi

I hold a leasehold plot in a society in pune,maharashtra. The society is the owner of the land for which they have already paid the stampduty on registered sale deeds.

The plot was alloted to me in 1980 vide a allotment letter, thereafter a lease deed was made on 14.05.1985 between society and me without any stamp paper.The lease is for 999 years

Now i want to register the lease deed, the society is ready to co-operate for the same.

My query is :

1. What is the stampduty payable on the said lease deed dated 14.05.1985.

2. What is the process to get it stamped and register the same ?

Please help

thanks