Attack within 0.61 meters?

I have an enemy-follow script. The script is here

var target : Transform; //the enemy's target
var moveSpeed = 3; //move speed
var rotationSpeed = 3; //speed of turning
var myTransform : Transform; //current transform data of this enemy
function Awake()
     {
     myTransform = transform;
     //cache transform data for easy access/preformance
     }

function Start()
     {
     target = GameObject.FindWithTag("Player").transform;
     //target the player
     }

function Update ()
    {
    //rotate to look at the player
    myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
    Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed*Time.deltaTime);

    //move towards the player
    myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
     }

I want to AI the enemy such that if it is 0.61 meters from me , it will fire. How can I do that?

Simply add a Vector3.Distance check:

function Update () {
    if(Vector3.Distance(transform.position, target.position) > 0.61) {
         //rotate to look at the player
         myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
         Quaternion.LookRotation(target.position - myTransform.position),rotationSpeed*Time.deltaTime);

         //move towards the player
         myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
   }
   else {
      //Attack Code Here
   }

}