After entering your 1099-INT, two screens later, you'll be asked "tell us if any of these uncommon situations apply". If you answer "None of these apply", the next screen will ask "Which state is your $#### of exempt interest from?"
When asked which state, check the box "I earned tax exempt dividends in more than one state". In the drop down menu, select your state and enter the $ amount you calculated. In the 2nd box, select "More than one state" (at the bottom of the scroll down list) and enter the remaining dollar amount.
