I PM I, Brian and after that he sufered a chest pain attack

I decide to post a real example of my case.
I used to have in my page title this:
Best hotel rates in Hermosillo - bla bla bla (
www.hermosillo-hotels.com)
and I was #1 with the query "hermosillo hotels"
Then I began to see my page falling down positions and being replace by sites with the page title Hermosillo hotels, bla bla bla...
Then I change my page title to Hermosillo hotels Mexico - bla bla bla...
(
http://www.hermosillo-hotels.com)
And my site disapear from the face of Google using the query Hermosillo hotels.
I made this change like a month ago.
Can you tell me what I did wrong?