Can I amend a return not filed with turbo tax?

Yes, you can.

You can amend your 2016 tax return with TurboTax if your return was prepared elsewhere, but it's not necessarily an easy process. You need to recreate your return by entering information in exactly the way as how it was filed, then go through the amendment process for that return. ( Federal Taxes / Other Situations / Other Tax Forms --Amend a return and select Start )

To purchase one of the TurboTax programs for 2016, see

https://turbotax.intuit.com/personal-taxes/online/

[Edited 3/12/2017]

It's for a prior year. It's my 2016 return.

See updated answer above