Most of the women available live faraway in the suburbs, so you need someone who is around your neighbourhood. You may try asking the doorman, neighbours, shops around your house. I heard of people who found very good personal domestico at the nearby churches.
I would love to pass my resume along. I am 22 and moved to Buenos Aires two months ago. I am a long time babysitter and have experience working as an au pair. Feel free to contact me, email@example.com