The Brazilian currency is Real. The conversion rate is US$1 ~ R$5-6.
It would be better that you rent a car at the airport. Most of the cars are stick shift, so if you don't drive stick shift, make sure you ask for an automatic. Traffic laws are pretty much the same, but no turn right on a red light (never). If you have any questions, ask the bride and groom, and they will be happy to help.