30 March 2013
First clarify is date of incorporation is 12/03/2013 or 12/03/2010, because of with out incorporation of firm a firm can't start business. So i asked that question. please confirm that.
any way you can file returns for such Assessment years now. For A.Y 2011-12 due date is 31-3-2013 u/s 139(4) and for A.Y 2012-13 due date is 31-3-2014 u/s 139(4) and for A.Y 2013-14 due date is 31-3-2015 u/s 139(4).