It will be hard for you to just find one out of blue like that... You have to ask around to women that wear their hair straight and women who 'look' dominican. Ask where they get their hair done. Are you looking for a relaxer or for the GDB (Great Dominican Blowout).
If you want only a relaxer, then go to a good African American Hair Salon - you can get similar results. If is for the blowout look, then go to a Caucasian Hair Salon instead.
Been there, done that... got the T-shirt!
PS - if you need tips on how to style your hair at home so that you can eventually tame it to look like a dubbie... let me know.