Here is a list of ASA schools outside of the U.S.:
Outside the United States - Sailing Clubs | American Sailing Association
There are probably other international schools that others could mention.
Since you have had a couple beginner courses, my suggestion is to buy a smallish boat and sail it. You can take all the courses you want but it's also about getting out there on your own and sailing. If your goal is a captain's license, find out the criteria in whatever country you'll be obtaining the license in and just...sail...and work toward ticking off whatever it is you'll need to obtain the license. Log your sea time as, in the U.S. at least, you must have a certain amount of sea time under your belt in order to qualify.
If you are this new to sailing, you probably have not yet experienced everything that goes along with it (maintenance, storage, repairs, more repairs, etc.). I get the feeling from your wanting to "learn sailing as fast as possible" that you're more focused on the business end of owning a charter boat rather than sailing for the sake of sailing. Which is fine, I suppose, but a shame if you don't get a chance to appreciate the aesthetics of sailing.
In addition to sailing, courses in weather, basic electronics and engine repair would also benefit you as a captain.