The Episode 3: Long Road Ahead Add-on for The Walking Dead (Xbox 360) has 8 achievements worth 100 gamerscore.
Complete Episode 3: "Long Road Ahead"
Complete chapter 7 of episode 3.
Complete chapter 6 of episode 3.
Complete chapter 5 of episode 3.
Complete chapter 4 of episode 3.
Complete chapter 3 of episode 3.
Complete chapter 2 of episode 3.
Complete chapter 1 of episode 3.