Read the book, and do whatever exercises you can from the book on the whiteboard. Talk out loud, the way you will in the interviews. After a few weeks and 60 hours of doing this, you'll be ready to blow the minds of the people interviewing you.
When you go to your interview, you will bring your own markers. Then you don't have to deal with the fat, half dried out stuff you encounter during the interview. Also, warm up for an hour or two before you go to the interview, by doing problems from the book on the whiteboard, out loud. This helps you leave nothing to chance, and be ready for whatever they throw at you.
Yeah, it's a waste of time. But you have to play the game. Similarly, when they ask you why you left your last job, lie and tell them you'd accomplished all your goals there, got everything lined up and nailed down, and you're ready to make something happen somewhere else. Don't tell the truth if it's because your managers couldn't care less about doing what's best for the business. If you want to work at the circus, sometimes you gotta jump through some hoops. Big deal, you'll be ok!
Yes, the interview process is broken, but you can actually work at it and do well, even if you're old.
Buy this book even if you're not planning to take my advice and study. Even if you don't study, this should become one of your most treasured books. I myself was amazed at how many things turn out to be graph problems, and had a great time going through this book.
[1] http://www.amazon.com/Algorithm-Design-Manual-Steven-Skiena/...