I want to adopt my soon to be step son.?

I am getting married this coming November to my fiance. She had a son with another man 4 years ago. I have been the father figure for the boy for the last two years and he calls me dad. The biological father lives in Venezuela, isn't a u.s. resident or u.s. citizen, doesn't have a visa, he has never paid child support, he hasn't contacted us in over two years, and he is not on the birth certificate. We live in florida and I want to adopt him. My wife also wants change her name and the boys name to my last name once we get married. Where do I start with the adoption process ? Do I have to wait till were married? How long does the process take and do we have to get any sort of consent or approval from the biological father for me to adopt him?