After the trip to Ternopl, I noticed my passport was gone right in the same day that the visa would expire. =/
So I called the Brazilian embassy in Kiev and they told me that I should go there (means 10 hours of train) to get a new one. The good thing is that they would give it to me in the same day.
So I came to Kiev, found the embassy and talked to the staff which gave me the new passport in the same day, as promissed! Bad thing is that the old one was becoming full of stamps and visas and this one is completely empty: must travel more!
But still the best part is yet to come: after having a very short contact with the embassy staff I had one of the BEST ideas of the last years regarding my profession!