"I would be reading your book, but I have to work."
Translation:Czytałbym waszą książkę, ale muszę pracować.
"książkię" has a typo, but as a fun fact I can tell you that this would work in the so-called "Gwara warszawska" (Warsaw dialect). The -kę/-gę endings in this dialect sound rather like -kię/-gię or (given that it's a final-sound ę) even -kie/-gie. But I have lived in Warsaw all my life and I really seldom hear it.
"twoję" is not an existing form. In Accusative (which "czytać" needs) feminine nouns end with -ę, but their corresponding adjectives and possessives end with -ą.