I want the camera, which is following my spaceship, to rotate to wherever the cursor is looking

Hi,

I am writing a very very basic space game. i have a spaceship flying around and the camera following it, but i dont want the camera to center the view on the spaceship but rather to follow the mousemovement, so i can aim and shoot at other ships and control my spaceship seperately.

here is my cameracode so far, im happy with it following my ship, but i have no idea how interacting with the mousemovement works...

 using UnityEngine;
 using System.Collections;

 public class Camera_follow: MonoBehaviour
 {
 public Transform target;
 public float distance = 3.0f;
 public float height = 3.0f;
 public float damping = 5.0f;
 public bool smoothRotation = true;
 public bool followBehind = true;
 public float rotationDamping = 10.0f;



 void Update()
 {
     Vector3 wantedPosition;
     if (followBehind)
         wantedPosition = target.TransformPoint(0, height, -distance);
     else
         wantedPosition = target.TransformPoint(0, height, distance);

     transform.position = Vector3.Lerp(transform.position, wantedPosition, Time.deltaTime * damping);


     // smooth camera  focus on object
     if (smoothRotation)
     {
         Quaternion wantedRotation = Quaternion.LookRotation(target.position - transform.position, target.up);
         transform.rotation = Quaternion.Slerp(transform.rotation, wantedRotation, Time.deltaTime * rotationDamping);
     }
     else transform.LookAt(target, target.up); 
 
     }
 
 }