Spring or Fall? ASU or higher ranked?

I’m an international freshman accepted to ASU for Spring 2016 for Computer Science (BS), have applied only to ASU as of now cos my SAT score is just a 1520/2400 (I didn’t study at all), I’ve been taking lotta practice tests and my scores have improved to 1800 and once even a 2000 FYI. I’m forced to take a gap year because I hadn’t taken the SATs during high school. But if I choose ASU for Spring 2016, I’d be taking only a 6 month gap between high school and college. I guess gaps don’t make a huge difference unless I’m wasting time, but there’s nothing I can do much as I’m stuck between preparing for the SAT again or choose ASU.

The reason I applied only to ASU with a 1520 is cos its ranked 182 in the world according to the Times Higher Education Rankings 2015 and other choices for CS either require a better SAT score, have higher overall fees, or don’t have too many international students.

My question is, should I choose ASU and go in Jan 2016 or try the SAT again in October and then apply to better universities (my current SAT score isn’t that great) but my fee budget should be less than 46000$ (overall per year), and as you know there are no SAT exams between June to Oct and the ACT in Sept is closed for registration so by the time my scores are out Spring 2016 admissions are closed for international students. I tried asking Ohio State if they would accept my SAT scores a little after the deadline for Spring 2016 applicants but they said they can’t do that.

I’m confused as to which step to take. If I choose to write the SAT again in Oct I’d have to say no to ASU (I know my application is valid for three semesters) for Spring 2016.

I do have extra curricular activities (Trinity Guildhall Piano for 9 years, Robotics, Trekking, School competitions prize certificates) but no AP classes or honors during my high school. My GPA would be around 3.0 or 3.2 (On a 4.0 scale)

What should I do? Please read from the beginning if my post seems a little confusing at first, or ask me questions if you do have a solution for me but need more facts.