Your best option is probably to switch to the CD/Download TurboTax software.
How do I switch from TurboTax Online to TurboTax CD/Download?
Another option, if the explanation statement is the only thing that TurboTax Online can't handle, is to prepare an explanation statement yourself on paper. Then you would have to print your tax return, sign it, and file it by mail, with your paper explanation statement attached. Put your name and Social Security number at the top of the explanation statement, and attach it at the back of the return, after all of the IRS forms and schedules.
Of course, another option is to go to a local tax professional to have your tax return prepared and filed.
