Recharging Old Book

How does an author recharge an old (older than 5 years) book?  Like most folks when I'm looking for a book on a particular topic I search for the title with the most recent publication date.  However, that doesn't always mean I'm going to get the best book!

UnBreak Your Health is an easy-to-read and understand collection of all the therapies and treatments outside mainstream medicine today.  Some date back thousands of years, some are much newer.  While every therapy will work for someone, I doubt many will work for everyone.  That's the challenge of complementary and alternative treatments.  Even more difficult is the fact that patients/customers must take responsibility for their own health. 

The second edition is now 11 years old, it was published in 2010 in both hardcover and paperback.  I've done everything I can think of to promote it.  There are over 60 podcasts on the book's website and they're as true today as the day they were recorded.  I've been on nearly 70 radio or podcast health shows talking about it.  I've done Twitter and obviously this blog along with many other websites.  Sales have continued to slow down over time which is normal, but I'd like to reinvigorate my book because I know it can still help people find better health.

Any ideas or suggestions?