There is a sign posted at entrance to casino that I saw yesterday when going to gym. It said that close to ring tickets were US$100 and $80, and this includes, as I recall, drinks, and general admission is US$20 or $30. I will walk past later today and check the sign again so I can confirm the general admission price. Will also if it says where to get tickets. Fists of stone Doran is one of the fighters, according to the info posted.
There was an interesting piece recently in a Spanish language publication based on an interview with the man who now has the casino building concession. It said his business in the US is both casino operation and fight promotion and that he intended to bring top fighters to Sosua. This will be the first of what he said will be many.
The location of the fight is the casino building of Sosua Bay Hotel. It will be on the 2nd floor in the large auditorium.