Babysitters/short term nanny (Buenos Aires)

Hi there,
We are in Buenos Aires for a couple of weeks and we are looking forward to seeing the sights. Some of which our 2 year old and 3 year old would love and others that they just would not. Can anyone recommend a babysitter/nanny or agency that we could use? Obviously we'd like to see references etc. Any suggestions would be greatly appreciated.
Thanks,
Candice