Hey Claudia,
I'd love to work with you for this project. I'm new to freelancer.com but I am a successful freelancer as well as fulltime software development engineer.
What CMS is your website built in? (It looks like it could be wordpress, but perhaps its just a template-based html/php site?).
I'd like to discuss your project more in depth. For starters, are you keeping track of how many views your page has? Perhaps there are other factors for why the book isn't being downloaded/purchased.