Chaser Models

How would one go about getting models from the game Chaser into Garry’s Mod? Is it even possible?

Example: MARSCORP Red Commando
http://www.deafgamers.com/chaser_reviewpic3.jpg

Example: Montack City Military Unit Soldier
http://imageshack.us/f/842/chaser2012011016430172.png/