I received an extension to January 2018 because of Hurricane Irma but now I can't access my return that I already payed TurboTax for. How can I continue the return?

2016 is now considered a prior tax year in the TT world ... if you already paid for the ONLINE version contact TT support to get a download pushed your way ...   

See this TurboTax support FAQ for a contact link and hours of operation -https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number

How to complete a started prior year return :

See this TurboTax support FAQ on completing a prior year tax return started with the online editions - https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turb...

Thanks for the quick answer Critter#2. I will call on Monday. 🙂