Universities for U.S citizens?

Hi!

I am not well aware, whether you can convert your visa from the tourist to the study visa being here. In case, if you need to move out of Brazil, you can go to a neighboring country to apply for the visa. Although I am not well sure about these things.
     
Regarding the Universities, every university here in Brazil accepts anyone from anywhere in the world. Though there are some requirements. For doing graduation,
I think it may be competitive to get admission and far more competitive to get funding. If you are looking for postgraduate studies, then it may be easier depending on the institute and the university you want to enter.
    Well, I am doing postgraduation (Ph.D.) from the University of Sao Paulo, which is among the best university in Latin America. So, for postgraduation (Masters or Ph.D.), you must have an agreed supervisor to guide you through the project. For this, you need to send emails to the supervisors about the research you want to do, etc, (can find their addresses on universities' websites). Should include that you want scholarship too. So the supervisor can inform you, whether he/she has a project for you and funding etc. Normally every institute has some funding but may be competitive.
          You must speak Portuguese, Classes are mostly in Portuguese but the material is in English most of the times. For passing Portuguese test, there are different rules. In my Institute, I had to submit Portuguese Proficiency until 18 months of the admission. However, I could do this within 10 months.
     Depending on the institute, you may have to pass a written subject test, that may be taken in English.
     Don't forget to get stamped your degrees and certificates from the embassy of Brazil in your country.
                 If you have any doubt, you can ask me, however, the first step to getting into Postgrad studies, is to contact a supervisor.

               I hope this information help you, Thanks!

Cheers,
El Hasan