It return

I have not filed it return for FY 2011-12 and 2012-13.  Can I do it offline or online without penalty.

If my income is below 5 lacs , is it mandatory to file it return.

Last it return i filed for FY 2010-11(AY 2011-12).

Can I skip last two FY - 2011-12 AND 2012-13 and file it return for 2013-14 in case penalty imposed for late filing.