<p>I agree with the other posters. It would be best to retake the SAT, and aim for a 2300+. It is pretty easy to improve- I started at a 1600 on practice tests and broke 2300 on my real exam. Put heavy focus on the Critical Reading section- there is a lot of good advice on how to improve it on college confidential.</p>
<p>Also, try applying to some more American colleges. I know that Stanford and Harvard are very nice, but there are many other good colleges in the US too: namely, MIT, Yale, Columbia, U Chicago, and even UC Berkeley. If you are going through the effort of studying for the SAT, might as well submit a few more applications :)</p>
<p>As for chances, I would say you have around a 20% chance for both Stanford and Harvard. I would suggest applying SCEA to Harvard (better chances + your extracurriculars seem like a better fit), in which case you would have around a 35% chance of admission. </p>