how to move part of the model when it in an animation loop

Hi, I'm trying to make an over the shoulder shooter game. I have an animation for when my character is standing still and aiming, I want my character torso, head and hand move with my mouse while the animation still playing but it not working. I only work when I turn off the Animator, so I guested the torso does move but it position got reset by the animation. Both the model and animation are downloaded from the internet.

Sorry for a very rough explaination because my English is not decent.