Marc,

Here's the general information page for visas from the consulate in Atlanta which is the consulate you have to use. (Visa Information - Atlanta) It should answer most of your questions.

If you apply in person, you may pickup the visa the same day. The fee is $160. You can also get the visa by mail which takes five business days. The fee is $180. As far as I know, Arlene would not have to accompany you. That is the practice in other Brazilian consulates but you should check with the consulate by email because each consulate has slightly different rules. Good luck.