Had my passport stolen in Lima, and had to get a new Brazil visa in a hurry. It was impossible trying to replace it in Buenos Aires in the time frame, so we waited till we got to Puerto Iguazu. They weren't interested in the photocopies of the originals, or original application form, so had to start from scratch. Opening times of the consulate are 7am-1pm Mon-Fri. To make things easier, you should take with you a printed copy of an application form you should have lodged online (no earlier than 1 month before the day you go to the consulate), a passport photo and 147 Argentinian pesos (if you are Australian). To lodge the form online, go to https://scedv.serpro.gov.br
The server may think this site is a security risk, so you have to bypass this.