How to make bullet shoot in same direction as player faces in 2D Top Down Shooter

hi, This is a 2D game. This is the code I have put together for when the player presses the left click button an object should fire towards move in the same direction of the player, I think the code might be right but Here it is:

using UnityEngine; using System.Collections;

public class PlayerShooting : MonoBehaviour {

 public Rigidbody2D bulletPrefab;
 public float attackSpeed = 0.5f;
 public float coolDown;
 public float bulletSpeed = 500;
 public float yValue = 1f; // Used to make it look like it's shot from the gun itself (offset)
 public float xValue = 0.2f; // Same as above


 // Update is called once per frame
 void Update()
 {

     if (Time.time >= coolDown)
     {
         if (Input.GetMouseButton(0))
         {
             Fire();
         }
     }
 }

 void Fire()
 {
     //Rigidbody2D bPrefab = Instantiate(bulletPrefab,transform.position,Quaternion.identity) as Rigidbody2D;

     Rigidbody2D bPrefab = Instantiate(bulletPrefab, new Vector3(transform.position.x + xValue, transform.position.y + yValue, transform.position.z), transform.rotation) as Rigidbody2D;
     bPrefab.GetComponent<Rigidbody2D>().AddForce(transform.up * bulletSpeed);

     coolDown = Time.time + attackSpeed;
 }

}

, I am not sure what to put where in the hierarchy, anyway can someone help me with this please? I have the "Player_Hero" and that is all, i have a image for the sprite but, i have put that under the "Player_Hero" this is called (Fire_1) as it is a spell :) yeh please can someone help me?

Thank_you();