J.R. Martinez jived his way to the “Dancing With the Stars” mirror-ball trophy, and now he’s planning to write a book. The Iraq vet, motivational speaker and actor is writing a yet-to-be-titled tome which will tell his life story. His rep, Cynthia Snyder, says the book will be “full of things people don’t know.” Martinez began the writing project before “DWTS,” but his win boosted interest, and he has meetings with publishers next week to shop it around. He’s also headed to numerous auditions after his dramatic defeat of Rob Kardashian and Ricki Lake on the dance competition’s finale. “He definitely wants to act,” Snyder says.