If you are looking for a good Italian option and you are not very price sensitive, try Villa Tevere out. I personally like the Raviolis, Gnocchis and the Tiramissu. The decor of the restaurant is quite exquisite too.
For more details, visit the restaurant´s website. Expect to pay between 200 - 300 reais for two people, including a wine.
http://www.villatevere.com.br/