Getting US dollars and Euros in cash is pretty hard in Brasilia and most people go to one of the money exchanges places or their banks, which costs an arm and a leg with charges and fees.
Bank Bradesco in SEPS712/912 is to our knowledge the only bank that has a ATM that spits out US dollars and Euros with your cash or credit card from your country.
We are not sure about the charges and fees as we did not try it ourselves. But if you are in need of these currencies in a hurry, it might be worth a try.