Many nations have consulates in Rio de Janeiro. If you in any way need help the consulate is a good place to go. All of them don´t work well, but they should be at your service, after all they are funded by tax money right. To find your consulate go to
Rioturs list of consulates
. This will take you to a list of all the consulates. Unfortunately addresses change a lot so it´s a good idea to confirm with your countrys homepage for foreign representation (if any) or just simply make a phone call.