For 2015 you have to buy the Desktop program.
https://turbotax.intuit.com/personal-taxes/past-years-products/ You will have to print and mail prior year returns. And send each year in a separate envelope so the IRS doesn't miss any.
For 2016 you can use either the Online version but only until Oct. 16, 2017
Or buy the Desktop program,
https://turbotax.intuit.com/personal-taxes/cd-download/ You can efile 2016 until Oct. 16, 2017 after that you will have to print and mail.
If you buy the Desktop programs they all have the same forms and the Desktop program can do more than 1 return if you want to file separate returns again. Does she need to file 2014? If not then you probably should amend your 2014 return to Joint to include her. You will get another personal exemption and a higher Standard Deduction. So you may get a refund.
