The Coursera recommendation is spot on. MIT Open Courseware would be worth looking into as well. Studying a few mathematics and programming courses would put OP in a much better position to determine the next steps.

I finished a comp sci degree with a major in computational mathematics and I don't feel like I could accomplish very much with my bachelor level skillset in an industrial context. I didn't learn enough mathematics in 1-2 years to be a good applied mathematician.

I wish I did a mathematics degree in hindsight!