Hi there:
You should be able to find some dancers supplier shops in Miami. Look them up in your local yellow page. It is the best way to try a pair of shoes on before you buy.
One of the largest competitions in United States, USDSC, will be in your city starting September 4th. Usually there will be many dance shoes vendors partcipating. Here is a link to this comp:
http://www.usdsc.com/index.cfm/showsection/winners_circle/page.htm