Unless you want to pay for simultaneous translation, I'd suggest you just arrange to have your speech translated ahead of time and ask for a volunteer at the conference to read it out for you. Of course if you are going to speak extemporaneously this won't work. Same if you intend to field questions from the audience.
You should be able to find translation services by googling and make arrangements. Depending on the nature of the conference and how much of a Big Deal they consider you, you may very well be able to have the organizers handle all of this for you. Check with them first.