Currency exchange question (São Paulo)

Hi all, Can anyone please advise on the most inexpensive ways of exchanging Brazilian Reals into US Dollars or UK Pounds, and transferring the money into a UK or US bank account?

I'll be exchanging Reals into UK Pounds soon and into my bank account in the UK (ideally), but I'm trying to avoid the high bank charges and exchange rates in the process if possible.

If anyone has any tips or can point me in the right direction for any previously posted info on this I would be very grateful.

Cheers,
James