Too Late now...can't file for an extension after midnight:
Just keep working on your file, and try to get your main tax return e-filed sometime in the next two weeks.
IF you end up with a Fed refund, there no penalty for a late Federal E-file (many states follow the same, but I don't know if all do)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*