You do not amend a tax return that was never sent to the IRS. You mail the original return that was prepared and never filed. If you have a copy of it, just mail it to the IRS with copies of all W-2s and any other form that had federal withholding. Make sure you sign and date the return.
You can no longer prepare a 2013 tax return using TurboTax since TurboTax only supports preparation software for 3 prior years. You can no longer get a refund from a return that is for a tax year prior to 3 tax years ago.
