I know a college student who's fluent in English/Spanish. He's on his way back to Santiago on Saturday after working his 3rd summer in the U.S.
I'm certain he could accomplish what you want & likely at a much lower rate than a translation service.
If interested, send a private msg or post your e-mail address if you want me to put you in contact with him. You can e-mail or call him before you arrive & decide for yourself. Actually, he's in U.S. until this weekend so you could even call him on a U.S. # if that's where you're located at the moment.