Have you considered using "priceline". I have not yet tried it myself (but plan to do so the next time I want to spend a few days in Kingston). Here is a link to an earlier thread posted from a couple that did use priceline and wound up staying at the Wyndhan in New Kingston for under $100/nite.
http://negril.com/forum/showthread.p...ht=Trench+Town

Good luck - both with the hotel search and with your embassy appointment!