Paul, British Council (Xin-Yi Sec. 5) often has workshops for teachers. Many of these are aimed at local High School teachers, but may still be of use.
Upcoming topics are storytelling (14th Aug) and Project work (20th Aug). If you’re interested, call or come in to register (sessions are free). In terms of IELTS, the best way to improve your effectiveness, if you’re not already, may be to become an IELTS examiner. Cambridge is currently looking to recruit new examiners. Again, call or come in to find out more.
I don’t think qualifications like the ones you’re considering will give you significantly more earning power in Taiwan, at least not from what I’ve heard, so you might want to rethink that aspect.