You should (I hope) be able to transfer the funds through a financial institution like Banco Piano and you should be able to get a CDI from AFIP to buy the property in your name, using your passport.
That's what I did when I bought my apartment in Recoleta in 2006. I did not actualy use Banco Piano. I used another financial institution that was suggested by the real estate broker who had the listing for the apartment I was buying, but I don't remember the name of the finincial institutiion at the moment. I recently spoke with the real estate broker who handled the sale of both of my apartments in Capital Federal (in 2009 and 2010). after another expat asked the same question about how to get USD into Argentina to buy property. He strongly suggests using Banco Piano.
If you don't have a DNI you may not be able to transfer more than the amount stated on the escritura plus the escribano's fees and taxes. I am not sure about the current rules. My Argentine girlfriend in 2006 wanted me to send the funds from my bank to a "special account" her lawyer was going to open. She also insisted I put her name on the title or I would be arrested and go to jail for money laundering.
I dumped the girlfriend and the lawyer before the ecsritura and everything went well. The escritura took place in a private room of the exchange company I used to receive the funds sent from my US bank. I did not actually have to have an Argentine bank account to receive the funds and the property I bought was in my name only. No one ever came after me for, as my Argentine girlfriend actually said, "Washing the money."
