How can I(old house tenant) get property right in West bengal corporation area?

I have been living in a house as tenat since 1970 with 1120 square fits area. A promoter and my land lord want to construct a flat destructing the house where I live. I am claiming for a flat as compensation. but how much area can I claim for compensation at free of cost? I have 1120 sq fits at preasent.