Substitute Teaching in English (Bogotá)

I'm coming to Bogota from the U.S. in September to stay for up to 9 months, spending time with my Colombian girlfriend, and am wondering if anyone has done any substitute teaching or (non-EFL) tutoring with success there? And if it exists, would I need a work visa to do it?

I'm an experienced high school physics teacher who has also done a bit of EFL, and thought I would find a good job ahead of time (that hasn't happened). I'm not enthralled with the prospect of teaching EFL private lessons around the city, with what I've heard about the pay and what I know about the traffic and safety. Since I don't have a job yet, it looks as if I'll arrive on a tourist visa. And from what I understand, work visas need to be obtained from outside the country (is that correct?).

Thanks for any feedback anybody has!