Which English certificate test should I take?

Well at first let me explain my needs so you guys can help me out with this terrible doubt I've been facing. I've been studying English since when I was 10 years old at Fisk and stopped at 17 (now I'm turning 20 next month) on the last book. Since when I dropped off the English course, I started getting in touch with English in a different way, using all my English structure I already got, studying grammar from a lot of different websites and listening to podcasts and other sources. But I've been feeling since I left English school that I need something that proves I really know English and if it sometime in my live turn out to be necessary.

I tought TOEFL IBT would be my best shot but it seems to be for those who want to study abroad and that's certainly waht I do not want (I'm finishing Law University course and studying abroad is out of the question).

So I need you guys to help me out here:

1) Should I take some specific test like TOEFL

OR

2) Should I go back to FISK and fish the course to get my certificate.