Where to exchange dollars? (Buenos Aires)

I moved here a few weeks ago and I have some money I want to exchange unofficially to get the better rate. I went to calle Florida the other day and exchange a little bit but it scared me, thinking it was just too easy to get robbed. If anyone has a more or less trustworthy contact or any relevant information it would be greatly appreciated. Also, another question, my bank account has all american dollars in it (an american bank account), is there any way to extract dollars from it and not pesos (which are automatically exchanged at the offical rate when I use my debit card or take money from an atm). Thanks a bunch! Email me at Protected content thanks!