Get wage transcripts from the IRS. You can file 2012 - 2015 for refunds but not for any older years those are lost. (and the 2012 must be postmarked by 4/15/16 or that one is also lost).
You can get a transcript from the IRS: http://www.irs.gov/Individuals/Get-Transcript
After filing the 2012 - 2015 returns, if you owe taxes for the prior tax years you can work on those.
TurboTax Online only supports the
current tax year 2015. The 2014, 2013, and 2012 have to be prepared
using the desktop software (CD/download). Each tax year requires a
different year software; i.e., 2014 can only prepare 2014 return; 2013 software
can only prepare 2013 return, etc. Prior-year returns cannot be efiled;
they must be printed and mailed.
NOTE:
If you prepare returns for multiple years, do NOT mail them in the same
envelope. Mail them separately.
You can see prices for those 3 prior
years at the link below if ordered directly from TurboTax, but you may also be
able to find them at a discount at reputable retailers like Amazon:
https://turbotax.intuit.com/personal-taxes/past-years-products.jsp