I think you might have a 50-50 chance, but I would attempt to get the SAT at the 2350+ level by taking the Dec test. Also, if you show a strong passion in one area that corroborates your EC accomplishments/commitments (i.e. Student Gov't), that would increase your chances.
Also, try posting this in the regular thread (not the class threads). You will receive many more replies there.
And if you haven't already, try this thread to gauge your statistics/accomplishments against those who were admitted/waitlisted/denied last year:
**The Official Harvard University 2013 Decisions Thread**