Being in Buenos Aires, I would try to enjoy her unique treats. The city has a scene arts life that I think has no match all over the world. Start by checking the offering in the Teatro Municipal General San Martin and the Teatro Nacional Cervantes. I would not waste my time trying the comedies on Avenida Corrientes, but the off is amazing.
Walk the city's many neighborhoods and parks. Go to the Reserva Ecológica. Take a trip to the North and spend a day in Tigre. Eat every day in a different place. Visit the local China Town, in San Isidro. Pay attention to the programming in the Sociedad Rural, in Palermo. If Boca and River have a match, do not miss it.
I may be wrong, but I think in April is the annual Feria del Libro, one of the biggest books expo in the world. Explore the bookstores in Avda Corrientes, some open 24/7, and scout among the sales tables looking for some hidden treasure.