You need to file ITR 1 (ITR for Salary). You can file your return online and please take the format of ITR 1 from the link below for online filing:
https://incometaxindiaefiling.gov.in/portal/downloads.do
As per section 139(4) of the Income Tax Act, 1961, belated Return of A.Y. 2011-12 can be filed upto 31st March 2012 or date of notice issued under section 142 by the Income Tax Department, that time has already expired in your case, however you can try to file the return with payment of tax, if any with the required interest on delay so as before computation of your income by Assessing Officer on best judgment basis under section 144 of the Income Tax Act, 1961.
And for current year's return, you have time till 31st July 2012 for filing of the ITR.
I would request to all members of CAclubindia replying on this query, please correct me if I'm wrong anywhere.
Best Regards,
Priyanka