As for getting yourself legalized here, you don't have a whole lot of options. You can't sponsor yourself for a work visa, for example (aside from the fact you are working in the black)
The other requirements still stand - you need to be married to a resident or citizen, you need to be enrolled in school, you need to have a provable income outside of a job (rental income, investment income, etc) or you need to be retired, or maybe have a baby out of wedlock (I probably forgot one or two, but they are harder to qualify for I think).
Only other thing is wait a year or more and go for the citizenship route, but someone who has not had residency can't just go ask for citizenship (and expect to get it), the process involves lawyers and a lot of time and various amounts of money.
Although I do know a guy who successfully set up a trust in Panama, with the help of an accountant there and a lawyer here and he paid monthly income into that account and that money was paid to him (it looked like a trust, from people looking at it here), and immigration approved it. I wouldn't suggest this method as it is a fraud and not very likely to continue to be a means to get residency...
Also, I don't know anything about your prospective clients, but be careful depending too much on them, at least until you're established. I have found that monetary commitments can often be quite weak here.
And my wife is one of those "eternal English students". There probably is a market for alternative teaching methods here, if you can get away from those
stupid aggravating course books and audio CDs, which may work for some people, but from what I've seen through one of our girls and my wife, those courses aren't very effective (and I'm talking about a number of different courses, taught by private teachers or in classroom settings) and the majority of the people not getting anything out of it, certainly not speaking or writing English. Not to mention the one thing that always pissed off my wife - the teachers often refuse to say a word to them in their native language to explain anything! Immersion doesn't work an hour or two a day a couple of times a week!!!!
If my wife hadn't found someone already to help her and our girls (and the prof is doing a wonderful job - and she isn't a native speaker, either
), I'd be PMing you to sign you up as well