From what you listed, I think that is a very good skill set you have under your belt. I'd say that considering your situation, you should definitely use it to your advantage. And yes, believe it or not, earning $40-$50 per day is very realistic doing small freelance projects.
From my experience, what occupies the most amount of time when doing freelance work is not the actual development/testing, but having to communicate with clients, and reading/filtering out the job listings, and things of that nature. Regarding the whole experience of being a freelance developer, again, you can find plenty of articles and advice on this very forum, so I'll just stop there.
I certainly hope it works out for you. Try doing 1 or 2 projects and see how it goes, you know?