The author's message is one of hope.  At the end of the story, Tariq and Laila are reunited with their daughter and she gets away from the cruel and violent Rasheed. 

"Laila and Tariq run away with both children and live in Pakistan. But after the United States invades Afghanistan, the family returns to Kabul. Their love for each other, as well as their love for their homeland, despite its cruelties and harshness and hardships, ends the novel on a high note, suggesting the possibility of a better future."

The author's message is technically referred to as the  theme, which is the overarching idea that the author presents.  Generally the theme is a message about life, or the "moral" of the story. 

 When thinking about the theme of this novel, think about what the main characters learned.  Mostly, the women of the story learned the benefits and consequences of love, and how that love can destruct or compliment a person.