The currency in Brazil is the Brazilian Real. In November 2013, 1 Euro = 3.1 BRL. (http://www.oanda.com/)
There is an extensive network of ATMs in Brazil and most major international credit cards are accepted in hotels and restaurants. We recommend to bring with you an amount of cash as well (Euros/US Dollars), with good notes, so that you can change them locally at banks/exchange bureaus. US Dollars may also be used to pay for any excursions.
The amount of spending money suggested, is the minimum required to pay for your meals, drinks, optional excursions, entrance fees, local airport taxes and tips. The amount you actually need of course depends on your own spending pattern; therefore souvenirs are not included. We suggest an amount of € 300-350 per person per week.