I hope the above mentioned is not agriculture land , so as per section 112 of the income tax Act, LTCG on sale of Immovable property (other than House property) will be taxed 20% with indexation .so In my opinion you have to find out the Value of Land in 2001 from registrar office or register Govt valuers for cost of Indexation and LTCG . ( at present base year is 2001 for Calculation)
As per section 54F of the Income tax act, with subject to conditions in the section, you Can invest in purchase of residential property to claim exemption.
please wait for others opinion as well. or confirm with others also .