I think Gaucho may have more information.
I have been looking into buying an apartment in Buenos Aires.
Prices vary (like in any big city).
A new apartment in a very nice area will go for US$ 300-400 per sq ft or as they calculate in Argentina US$ 3000-4000 per sq meter.
The least expensive apartments I saw in decent area were older, not updated and less desirable buildings and those were running 1500-2000 per sq meter.
Even the really nice apartments are a third of what you would pay for a regular apartment in NYC, SF, Paris, Miami or Madrid and even less than what you would pay in London. The prices are good but that ain't no bargain.

I have not gotten into the legal issues but it is my understanding that you are better off getting a real estate attorney. It cannot be very difficult if there are ads for apartments in Puerto Madero in the Financial Times.

Please let us know how things work out.