Matter of due date on income tax return

GOOD EVENING SIR,

                                           I WANT TO KNOW ABOUT DUE DATE OF INCOME TAX RETURN . SIR PLEASE GUIDE ME BY GIVEN THIS EXAMPLE BELOW

                                                             SUPOOSE INCOME TAX RETURN FOR F.Y 2010-11 (A.Y 2011-2012. ) I WANT TO KNOW ONLY THIS THAT IN HOW MANY TIME I CAN FILL MY INCOME TAX RETURN FOR THE F.Y 2010-11 A.Y 2011-12. MEANS CAN I FILL MY INCOME TAX RETURN FOR THE F.Y 2010-11 A.Y 2011-12 IN 2 YEAR MEANS UPTO 31 MARCH 2013.WHEN I HAVE ANY TAX LIABLITY THAN I WILL PAY INTEREST @ 1% U/S 234A AND PENALTY UPTO 5000 U/S 271F.IF I HAVE NO TAX LIABLITY THAN I WILL PAID NO INTEREST OR PENALTY IF I WILL FILL MY RETURN OF F.Y 2009-10 AFTER 2 YEAR. THANKS SIR I WILL WAIT YOUR VALUABLE REPLY