Hi Aida,
You can find most of the information you need on the pica website...it has forms etc that you can fill in , in order to work in Jamaica. You will need a work permit, and you can apply to extend your stay in Jamaica as well.
  is the website...check it out!
Hope this helps. Electricity isn't as bad as people say....the same as my Canadian home, anyways.  There are prep schools that are mutlicultural...you should be able to find them on line. The prices vary...you have to check. Some are $400 us per semester.
Good luck!