One of the best ways to gain a new audience is through book signings at bookstores. However, Barnes and Nobles always welcomes authors who are will to do a big more than just sign their books. When you talk to the Community Relations Manager mention that you will be happy to read sections of your book, that will provide a much larger draw to their store.
Be sure to ask the CRM how many people typically sign up for authors of your caliber. You’ll want them to include a blurb about you in their newsletter and to post a large sign in their store window now less than 30 days prior to your signing.