Secular Jews? Converting?

My fiance is a secular Jew. We both have similar beliefs, however, I was raised a Catholic and broke away from the church during adolescence. His family would like for me to convert before we get married. I truly believe in the Secular Jewish views and culture and would really like to convert. Do I have to be converted by a conservative rabbi in order to be recognized by Israel as a Jew? Can a Secular rabbi convert me?