A few things:
*Going to Stanford summer school will do zero for you at a top college. It's open admission, anyone can go if they can pay. A letter from a prof who knows you for a few weeks? Probably worth very little.
*No college cares if you had only 2 weeks to study for the SAT. Don't take it until you know you're prepared. The number of times you take it and low scores will hurt you at many top schools.
*Your IB scores won't get you into a top school. I would work on those rather than attending summer school at Stanford. Getting all 7's will make a huge difference, though only 2 weaker HLs will all but keep you out of top schools.
You're not an international, you'll be treated as a domestic student. Top 25? Maybe at the very bottom of that with a 2200 SAT score, but probably not. Will Berkeley or UCLA take you if you're full pay? Maybe. But they have so much choice from Asia. Learn what's important to colleges and focus on that with the time you have left.