Using the "Stocks, Mutual Funds, Bonds, Other" interview enter the 1099-B exactly as it reads, including the "$0" cost basis shown on the 1099-B. Then using the mechanism provided by TurboTax, enter the correct basis. (On the desktop version you click "I'll enter additional info on my own" and on the new page that comes up enter the correct basis in the "Corrected cost basis" box. Presumably the online versions have something similar.)
You'll end up with the correct gain or loss for your sale and Form 8949 will be filled out properly, showing the "as reported" basis of $0 and your adjustment of that reported basis.
