Maybe she doesn't understand English?!
I'm not meaning that to be funny, seriously! - maybe that is the case? You mentioned she came from Brazil - can you find out if she was spoken to in Portuguese or English? Maybe she only knows 'no' in Portguese? On 2nd thought, even if that IS the case, it's irrelevant - she needs to know English now, huh?
Sorry I'm not of much help - it sounds like you are heading in the right direction with her - Good luck and keep us posted!
PS -
My puppy (almost 15 wks) knows her commands in English/Spanish. I use hand signals with her too, so I'm not sure if she's responding to just that, but she knows 'come!' and 'venga!' mean the same thing. Maybe you can teach your pup the same (English/Portuguese)!?