What is my liability of Capital Gains Tax?

Cost of flat/furniture & fixtures in 10/2005 was 15 lakhs. Proposed sale with furniture & fixtures in 10/2008 is 35 lakhs. What will be the long term CG payable? I am moving into another State where I may or may not purchase another flat. Decision on this will be taken by 03/2009. When am I liable to pay LTCG tax in case I opt not to buy a flat? Can the entire 35 lakhs be deposited in Bank FD and pay the LTCG tax by 06/2009 out of this if I opt against buying a flat?