NO. You cannot file 2 years of taxes on one return. Each year needs its own return.
The 2016 return can be prepared in either TurboTax online or one of the desktop products (CD/download).
The 2015 return can only be prepared in the desktop products. You can purchase the 2015 software as a download from TurboTax at the link below, or you may be able to find the CD or download for a discount at a reputable authorized retailer like Amazon, etc.
https://turbotax.intuit.com/personal-taxes/past-years-products/
The 2015 return must be printed and mailed; it cannot be efiled.
I would prepare the 2015 return first. Then you can transfer the *.tax2015 data file into your 2016 return.
