If you used TurboTax last year you will find your return by clicking on the "Previous Taxes" link on the "Tax Home" screen.
If you didn't use TurboTax last year, you can use the following link to go to the IRS's website and request an online copy of your transcript:
https://www.irs.gov/individuals/get-transcript
Then once you have your transcript from the IRS you'll be able to use your AGI to file this year's return.
