Here is some tips for good and not to expensive wines when you go to a restaurant in Buenos Aires:
-Alamos, (malbec or syrah)
-Septima, (carbernet sauvignon)
-Dona Paula, (pinot noir)
-Los Haroldos, (malbec)
And if you want some slightly more expensive:
-Alma negro, (misterio)
-Rutini
Of...