Working Visa. Can anyone help me?

I am an american who would be visiting Trinidad & Tobago, I also have a Trinidad & Tobago Passport, I have been to China on several occasions hoping to do business buying toys, but I would now like to apply for a Z type as an English teacher, could you tell me if while I am there I can obtain it and what do I need to present to your Embassy. The school plans to hire me in January or February. I would be in Trinidad on vacation for approximately two months. I would appreciate if you can give me an answer as soon as possible, I have my Tesol certificate, an AAS College degree, High School advanced English Pitman's certificate of London and 1 year experience teaching English in Venezuela. I was in Trinidad last month and was told by your embass tat I can obtain one if I also bring my Trinidad passsport along with my USA passport. Thank you for your honor of viewing my e-mail I appreciate it very much.
Enid Laukam