To access your prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the section Your tax returns & documents. Click on the Year and Click on Download/print return (PDF)
If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created. TurboTax does not store online any returns completed using the desktop editions.
Or go to this IRS website for free federal tax return transcripts - https://www.irs.gov/individuals/get-transcript
For a fee of $43 you can get a complete federal tax return from the IRS by completing Form 4506 - http://www.irs.gov/pub/irs-pdf/f4506.pdf
But for Online accounts only the last return done is saved unless you downloaded the pdf before you amended.
"Pre-amended?" If you did not save the original return as a pdf before you amended it, the original return was overwritten by the amended one.
Try getting a transcript from the IRS, or pay the IRS for a copy:
You can get a free transcript from the IRS or for a fee of $43, an actual copy of your tax return.