Which agreement should be made ???

Dear All, We are Pvt. Ltd. Co. and in the process of Expansion of the business, We want to purchase adjacent plot to the existing factory in the MIDC area. Said plot is allotted originally to one Company , MIDC & that Company has also entered into Agreement for lease with MIDC , after which that company was supposed to construct the factory on the said plot ,however that Company kept on taking Extension to the agreement for lease for the long period and finally agreed to sale the land to us. We agreed upon some consideration and finally got the MIDC permission for the transfer of the interest. while giving approval MIDC entered into tri party supplementary agreement to lease wherein MIDC has transferred all the rights of the earlier owner company to us on the basis of payment of stamp duty and transfer premium. How ever that tri party agreement only talks about the premium and stamp duty paid towards the tri party agreement and does not take any consideration paid by our company to first owner . Now my query is, we need to enter into agreement with the other company stating the amount paid by us to them . As earlier party has not eneterd into any lease deed with the MIDC can they come into any agreenment with us.what shall be that agreement needs to be termed as ...