Your chances are very low, bordering on impossible, for admission to UC Riverside or UC Santa Barbara with those statistics alone. Exceptional extracurricular activities, compelling essays, and strong letters of recommendation could *potentially* help, but they would need to be truly extraordinary to compensate for the low GPA. It's important to remember that many applicants with higher GPAs and comparable SAT scores are rejected each year.
Consider focusing on improving your GPA if possible through summer courses or retaking classes. You might also explore other universities or colleges that are a better fit for your academic profile.