Computation of long term capital gains tax payable

A plot of vacant land had a Fair Market Value, after indexation, as on 1/4/1981, of Rs.19,39,092/-. This land was sold on 25/7/2012 for a consideration of Rs.1,10,36,000/-. Rs.50,00,000/- were invested in 54 EC Long Term Capital Gains Tax Saving Bonds of REC & NHAI within 6 months from the sale date(25/7/2012). Kindly advise: 1)What is the amount of Long Term Capital Gain? 2)What is the Long Term Capital Gains Tax payable, including Cess, after considering the investment of Rs. 50 lakhs in 54 EC LTCG Tax Saving Bonds? 3)By which date should this tax be paid, considering that the assesee is a Senior Citizen and hence no Advance Tax is payable by her?