As you're entering stuff into the MFJ return, make sure you have TSJ codes turned on in the global options and make sure you are properly tagging every item with a TSJ code.  I don't know if Basic has the MFJ/MFS worksheet but you should be able to open your return in Professional and view the worksheet there.  You might be able to use the Pro feature to "Split return" to create two MFS returns.  Then you might be able to open both of those returns in Basic and go about your day.  If you're not printing or filing anything in Pro, you shouldn't have to authorize the returns (i.e. make a pay-per-return payment).  YMMV.