There are 2 possibilities of accommodation:

a) ATLANTICO Copacabana Hotel (conference location)
b) Private Apartment

Here are a few suggestions of apartments close to the ATLANTICO Copacabana Hotel.
#101A for $95US a night + a onetime $30US cleaning fee. http://www.gringomanagement.com/onebedrooms.html 

#101B for $85US a night + a onetime $30US cleaning fee. http://www.gringomanagement.com/onebedrooms.html 

#101D and #101E for $100US a night + a onetime $30US cleaning fee. http://www.gringomanagement.com/onebedrooms.html 

#102 for $90US a night  + a onetime $30US cleaning fee. \ http://www.gringomanagement.com/onebedrooms.html
#104 for $80US a night + electric + a onetime $30US cleaning fee. www.gringomanagement.com/onebedrooms.html
#117 for $110US a night + electric + a onetime $50US maid fee. http://www.gringomanagement.com/onebedroomspage3.html 

#126 for $110US a night + a onetime $30US maid fee. http://www.gringomanagement.com/onebedroomspage3.html 

#127 for $105US a night + electric + a $50US maid fee. http://www.gringomanagement.com/onebedroomspage3.html