I would agree with oddball if you didn't already have your undergraduate degree. An MBA is an add-on. Certainly getting a degree is a better option than going to Thailand and hanging around mooning over a girl and spending all your money on her, a common occurrance.

Again, I never met anyone coming to Thailand to do an advanced degree where the instruction is in English. You might look for programs from universities that are extensions of those in English-speaking countries. I do know that is fairly common in other countries. For instance, a major Florida university has a branch here in Panama City, Panama, and some Australian universities run programs in Malaysia. So there may be some in Thailand.

All universities are registered with the Thai Education Department, and you might find a list there. Another option would be to check with the UK, Australian, New Zealand, Canadian, and American consulates in Bangkok to see if they know of branch universities that offer MBA programs.