Now lets talk about extending your visa in Rio. First of all I will inform you about the rules.
Most Europeans and South Americans can just arrive in Brazil with a passport (for some South Americans an ID is enough) and a ticket leaving the country. If you are unsure about the rules for your nationality you have to check with the Brazilian consulate in your country. Most are granted up to 90 days on arrival that can be extended for up to another 90 days for some nationalities (I know for sure that EU-members are not given the extension anymore due to the policy of reciprocity). US-Americans, Canadians and Australians need to make arrangements prior to arrival. Make sure to check the stamp on the spot and point out to the issuer of the stamp if you intend to stay longer, if he refuses there is nothing to do; you’ll have to contact the Federal Police at the airport as soon as possible to see what they can do.
Much has been said on this subject, but this is how it is! If you are from a country that doesn’t need visa before arrival, you will be given a multiple entry 5 year visa. You can at no given point stay more than 6 months during a 12 month period, this is not at all thoroughly checked but that´s how the rules are. If you are from a country that need to make prior arrangements, like US, Canada and Australia, you´ll have to check it up since it varies. Many people solve this by overstaying and paying a daily fine (right now 2014 it´s about 10 R$ per day and maximum less than 1000 R$) on leaving, it can give you future problems though.
Prolonging Your Visa in Rio
This should be done more or less 15 days before the visa expires. Bring passport, entrance card, credit card (or some other proof that you have sufficient means) and a ticket leaving the country on a date within the 180 day limit. You may not need all of this but it’s better to bring. Procedure:
Go the Federal Police/Immigration, at Terminal 1, Red Area, 3rd floor, Aeroporto Internacional do Rio de Janeiro/Galeão Antônio Carlos Jobim, tel 3398-3142, applications open 8h/12h Mon-Fri. First you have to wait in line, then you get a form to fill in and information on a paper you should print out from a internet café they have closeby, you also will have to pay a fee in a bank. After this you return with the filled in form and the paid fee. All this is possible to do the same day. If you for some reason is denied, just accept the fact and leave, there is nothing to do and arguing won’t help. Getting your visa in Rio is probably slightly more complicated than in other states since there is a strong bureaucratic tradition here.
You will also be obligated to fill in an Entrance Card on arrival, the copy you will receive have to be presented on departure, if you don’t have it you will have to pay a pretty salty fine on departure, you might even be forced to return to your port of entry to obtain a new one. If it is stolen a police report stating that will avoid the fine.