What kind of license are you trying to convert? PPL, CPL or ATP? what kind of flying experience do you have and what do you wanna do? fly private or revenue? Btw, are you Brazilian? Did you attend school abroad?
All those are factors possibly contributing to extend the time for the convertion..
I recomend you to go to Rio to the Cemal to get your medical, as it is the most complete AMC and the most expedite in Brazil.
For the learning you can download the ICA-100-12/11 from the ANAC site, its about what you need to know...
For revenue flights the knowledge of the IACs and ISs, as well as AIP-Brazil are to be recomended, could also be asked in the checkride.
regards!