equivalent of a money order/traveller's cheques? (São Paulo)

Hi all,
We are trying to get a large amount of "cash" to pay a deposit for an apartment (we are only here for 5 weeks doing a short term lease). Do they have anything like a traveller's cheque or money order that you can buy with a debit card at a post office or bank?

We are sort of desperate--we have our 14 month old baby here, have had a really hard time finding an apartment, finally found something and they don't use paypal or google checkout so we have to come up with all the cash up front. We don't have a Brazilian bank account. The property owner is very nice and said he'd have taken a US check for the deposit but of course it never occurred to us to bring something like that with us.

Any suggestions would be well worth it. Thank you so much!!!