bachelor's is good, your experience will not serve you on a resume, merely help you do your job. Yes. Get TEFL certified in the U.S. (if that is your home country). It's easier for VISA puproses, and qualifies you upon entry as opposed to the "education" route.
If you're trying to land a job teaching English in Thailand, you would do best to have your TEFL and a bachelor's degree before you get there. Good luck finding a school to sponsor you for your visa if you don't.