First of all it seems like your family is being quite fanatic over your conversion. So I would not go head strong into the debate. Go up to them and drop these books on the table:
Catholic and Christian: An Explanation of Commonly Misunderstood Catholic Beliefs By: Alan Schreck
How the Catholic Church Built Western Civilization By: Thomas E. Woods
A Catholic Bible
The Catechism of the Catholic Church
The Catholic Way By: Bishop Donald W. Wuerl
And last but not least a book about the Early Church (Catholic Church)
These books should not only reduce their fanaticism, but also help to understand Catholicism, how it has helped the world, and the beauty of living as a Catholic. Feel free to read these books for yourself. Over half of them I have not even read yet, but I here that they are good and they sound good.