How to get the constant Y rotation of the camera

Question.... So I am trying to figure out how to change my movement controls depending on the Y rotation of the Camera.

This would be the code for just one of the 4 sides, but it seams to only check the Cameras Y rot at the start of the program instead of always checking it. I can not seam to put Camera.mainCamera.transform.rotation.y in a var.

This is in my Update function on the Prefab I am controlling.

 if ((Camera.mainCamera.transform.rotation.y < 137) && (Camera.mainCamera.transform.rotation.y > 51))
 {
     //Front Between 137-50 camera rot.y GP Movement
     if ((transform.position.z > 388.5) && (Input.GetKeyDown (KeyCode.D))) transform.Translate (Vector3(0,0,-33.5));      
     if ((transform.position.z < 392.5) && (Input.GetKeyDown (KeyCode.A))) transform.Translate (Vector3(0,0,33.5));
     if ((transform.position.x > -84) && (Input.GetKeyDown (KeyCode.S))) transform.Translate (Vector3(-33.5,0,0));
     if ((transform.position.x < 51) && (Input.GetKeyDown (KeyCode.W))) transform.Translate (Vector3(33.5,0,0));
 }