Have you considered Crowdfunding your book? If enough people have read it and believe in your message, you could use their testimonials to crowdfund it (lots of new websites who can help you here). I use my book to build credibility and to get me in the door of larger companies, then I "throw" in the book as a freebie when I'm negotiating my fee to come in and speak or train. Hard to explain my other thoughts through email (plus I need to know more about your subject, the book you've written, how much you're spending to publish it, etc.) so feel free to call me chat (for free, of course, at least for the first 30 minutes). 510-537-0107.

Ask first to see if anyone has ever done that task before and how long did it take them. I also find that when I have to estimate how long a task is going to take me, I close my eyes and visually imagine myself going through all the steps it will take to complete it. I then guesstimate the amount of time it will take and then add 25% extra as a cushion.

1. Have very high expectations that they will be your coach, not necessarily your friend (though many of my clients have become my friends, my first responsibility is to be their coach and focus on their business growth).
2. Ask around to the people you know who have a coach, Google "business coach in (your city), or RSVP to the many coaches who have posted answers here (myself included: I offer a free strategy session to see if we're a fit, email brad@bradwarren.com)
3. Ask what their business background is, and are they a "pure" coach (who only asks you questions and never gives advice) or are they a hybrid coach (like me. I make a distinction between coaching, consulting, and training, and I do all three depending on what you the client needs).
4. Depending on whether it's by phone or in person, the frequency, their level of expertise, etc., the fees can vary from $400 to $2000 or more per month.
Hope that helps. Again, email brad@bradwarren.com for a no-obligation session with me over the phone.