Instead of waiting for the file to be available to download, you always have the option of typing in the information yourself based on your paper or electronica copy of the Form 1099-INT. That way, no matter the reason for the delay, you can still move forward with your return.
When you are in the investment income section of TurboTax Online, choose 'enter a different way' at the bottom of the screen and then 'I'll type it in myself'.