No, you don't need to submit early (i.e. it doesn't help because they don't review applications until after the deadline has passed). So you have until Jan 15th.
Until then, it's a judgment call on your part. It seems like you have a hunch that your quant will still be an issue (it will be), but it comes down to how much time it will take away from your essays if you decide to prep for a re-take. If you really need to move heaven and earth to boost that score, at this point it may not be worth the retake - focus on the essays, and hope that what you have (intro accounting, your job, etc.) will be enough for the adcom to overlook your low quant score and lack of formal quant background. If the quant score was really just a "bad hair day" and you feel you can easily boost it without much additional effort, then by all means retake the exam.
Alex Chu
alex@mbaapply.com
www.mbaapply.com
http://mbaapply.blogspot.com