You should be able to download the file from your tax timeline on the website. After that, import it to your computer's turbotax software. I do this whenever I have to file an amendment. It is not necessary to type everything back in. I believe you can only do this with a return that was previously completed and filed online.

Also, tax laws can change after you file. TurboTax keeps these things up-to-date. I had to amend my 2014 return recently and the numbers came out differently. After speaking with TurboTax customer support they explained that their software is always up-to-date as laws change. This could have an impact when filing later or filing and amendment.