Ai instantiates Game Object but won't stop.

I have an AI script that is supposed to fire a bullet, the problem is that when it starts firing it won't stop. Can someone fix it?

Here is the script.

 var Player : Transform;
 var laser: GameObject;
 var MoveSpeed = 4;
 var MaxDist = 10;
 var MinDist = 5;
 var timer : float = 0;
 var timeLimit : float = 10;
 
 private var shooting : boolean = false;
  
  
 function Start () 
     {
     //start function
     }
  
 function Update () 
     {
         transform.LookAt(Player);
      
         if(Vector3.Distance(transform.position,Player.position) >= MinDist)
             {
      
                 transform.position += transform.forward*MoveSpeed*Time.deltaTime;
  
                 if(Vector3.Distance(transform.position,Player.position) <= MaxDist)
                     {
                         if(!shooting) Fire();
                     } 
     
             }
     
     }    
 
 function Fire ()
     {
         timer+=Time.deltaTime;
         if(timer >= timeLimit)
             {
                 Instantiate(laser, transform.position, transform.rotation);
                 yield WaitForSeconds(3);
     
                 shooting = false;                                
             }
     }