I don't think that your South American background is a weakness at all. Coming from a certain region or being of a certain nationality can hurt you if it's an overrepresented one, but I don't think that most schools (at least not in the U.S.) feel that was about Latin American applicants. I don't think that being from that region will necessarily help you, but it shouldn't hurt you, either.
You do have great multicultural experience, and I think that your language skills will also be a big help. Right off the bat, that makes me wonder if you have considered INSEAD, since they love applicants with multicultural backgrounds, and in fact they require entering students to speak more than one language.
Your Master in Int'l Business makes me wonder a little bit... Some admissions officers may see that and wonder why you pursued that, and ask why you now want an MBA. So, you will need to work through that. Your undergrad GPA is a bit low in an "easy" major (compared to engineering or science), so you will need to address that, too.
The rest will come down to the GMAT, the quality of your work experience, and your recommendations. If those are strong, then I do think you have a shot at top-ten schools.
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