The first thing we would want to do is help you define what is possible, and what your goals are. For example, is it possible for you to take classes in Korea? (From where you are from, you would probably find that to be relatively inexpensive). Are you wanting a professional level of command of the language? etc. Let me offer you a few methods that are available that I have experience with. This will likely take more than one answer.
If travelling to Korea and taking classes is a possibility, then I would recommend looking at the universities in Korea. Almost all of them offer immersion classes aimed at developing different levels of command of the language. I think most of them use curriculum developed at Yonsei, or at Seogang universities. The course I am familiar with is the one developed at Seogang University. In this one, when you pass level 3, you have a level of proficiency to allow you to take university courses. In fact, it is a prerequisite for foreign students at most universities. There are 6 levels available, though, and if you actually stay with it and pass level 6, you should have a level of proficiency to actually be a Korean teacher. (That's how level 6 was explained to me, anyway).
In these immersion classes, you spend 4 hours a day in class, and will have some homework. You will live in Korea so everything you do will be in Korean. The classes do not try to base themselves in your native language, nor in English, nor any other language. It starts out teaching you Korean, and in the early stages of level 1, this will involve a lot of pictures and gestures, but you will not be allowed to revert back to your native language because it is easier. The teachers will keep the class focused entirely in English.
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