Translation:I heard you won, congratulations!
The literal translation is "I was knowing that you won", but that's bad English.
The correct form would be "I knew that you won", but that's the wrong translation because it is saying that you had prior knowledge that they won.
The correct translation, (i.e the one that closely matches the Portuguese sentence's meaning and is also correct in English) is "I heard you won".
However, that sentence still has issues because it is idiomatic (since it is assumed that you did not literally hear that the person won), and the word "heard" is not in the Portuguese sentence.
An ideal sentence could be "I was informed that you won", but that too complicates it a bit more (who informed you? When? Where? How?)
"I heard you won" keeps it simple, is grammatically correct, and most importantly is an accurate translation.