I would recommend jumping in the deep end and start reading primary sources from the east and west and all the places inbetween. Once you start reading and searching - perhaps university library catalogs, you will find many more. Guttenberg and other free ebook sources are great because most of the greats are well out of copyright.

Kant "Metaphysics of Morals"

Singer "Animal Liberation"

Plato "Repulic"

Einstein "Philosophical Works"

Hobbes "Leviathan"

Rousseau "Discourse on the Origin and Basis of Inequality Among Men"

I have a degree in Philosophy and it is the best thing ever.