The Pousada Do Lago (http://www.pousadadolago.com/) is a family-friendly hotel near the centre of the city of Brotas with good facilities that include sauna, outdoor pool and tennis-courts. The hotel staff will happily book tours and activities for guests and have extensive information about the long list of eco-tourism options in the area.
Accommodation prices are in the region of about R$60 (about 23 Euro or $36) per night for a single room to about twice that for a quadruple room. It will help if you (or someone you are with) speaks Portugese - Brotas is principally a holiday resort for Brazilians and does not make extensive efforts to provide special treatment for those from father away. Note also access to a car will be important to get to the eco-tourism activities - many are about 20-30 minutes drive away.
