Make sure the schools know you are planning to take courses in January. Also, if there are any additional updates that would strengthen your application I would write a formal letter to the school addressing these activities and your interest in the school. That might help.
The earliest interview invites you may receive will probably come after the Pre-Dec acceptances have been processed, so maybe early January? If you put up your stats, people can give you better advice. Don't give up though! I've heard of people getting acceptances up to August. Keep your head up!