Just doing the IB will not get you into the top universities. A score of 1500 and above in the SAT could increase your chances of getting in. However, it is hard to assess solely based on your SAT and IB score. You must show that you are a well-rounded student by taking part in various extracurriculars and cocurricular activities. Another major aspect in your application is the essay. If your college essays show who you are and what you are passionate about, then you might just stand a chance.