Why didn't my Android auto adjust to daylight saving time and how to fix it?
You will need to research how to set this on Galaxy Nexus and Jelly Bean, but ..



You are currently using "GMT -03:00, Brasilia Time", and this does not include Daylight Savings by default.

You need to instead use (one of):

 America/Bahia
 America/Sao_Paulo


These all use UTC -2:00 for DST.

See:
Wikipedia: Time in Brazil