Hi!
To everyone going to Argentina I can highly recommend Verbum Spanish school in Buenos Aires
If you are looking for a personal, efficient way of learning Spanish, then this is a very good option.
I have studied at Verbum on two occasions and have always received a very warm embrace by all the staff at the school and the families with whom I've stayed.
The professors do an excellent job of assessing each student at his or her level and providing just the right instruction to increase skill levels. They manage to make the learning both challenging and fun. I have seen great improvement each time I attend.
Good travels!