Hi FlyArgentina,
Without paying much attention to the comment about Malvinas/Falkalnds just to avoid getting into a bitter subject I tell you that I've got my wings years ago in Aeroclub Rosario.
It is unlikely that you will just show up and be able to take an aircraft for a spin. Your license will be fully recognized but you will have to enrol in the club and ( if not a full conversion) do a proper adaptation. The field is non towered so only basic Spanish will be needed. The view of the Parana river with the islands is simply beautiful, specially early morning or at sunset.
If your wife is Argie then have her calling the club on 0054 341 4253100 and speak to Ana Maria, club secretary for more info.
Good luck to you
PS: an honest piece of advice....whatever you think about Malvinas/Falklands, keep it to yourself if you want to make good friends and have a great time. It is a very sensitive matter, to say the least. Just a thought.
Cheers and hope you enjoy my city.