How to change in to if move

hey guys i have a question aboute the player run animation i have this script but it is not working propperly and i want to change it to if movedirection forward &backward left and right but i dont know how to do that so thats the question

 using UnityEngine;
 using System.Collections;
 
 public class PlayerUTRAnimations : MonoBehaviour
 {
 
 
 
     public float minimumRunSpeed = 1;
     public float speed = 1;
     public GameObject Player;  // this is assinged becouse have al mt weapons attached to a box with the animations on it
 
 
     // Use this for initialization
     void Start()
     {
         GetComponent<Animation>().CrossFade("Idle");
         GetComponent<Animation>().wrapMode = WrapMode.Loop;
         GetComponent<Animation>()["Idle"].layer = -1;
         GetComponent<Animation>()["Run"].layer = -1;
 
 
 
         GetComponent<Animation>().Stop();
 
     }
 
     void SetSpeed(float speed)
     {
         
         if (speed > minimumRunSpeed)
             GetComponent<Animation>().CrossFade("Run");
         else
             GetComponent<Animation>().CrossFade("Idle");
     }
 
     // Update is called once per frame
     void Update()
     {
         if (Input.GetKey("w"))
             GetComponent<Animation>().CrossFade("Run");
         else
             GetComponent<Animation>().CrossFade("Idle");
 
         if (Input.GetKey("s"))
             GetComponent<Animation>().CrossFade("Run");//this is later changed to an other animation running backwards
 
 
 
         if (Input.GetKey("a"))
             GetComponent<Animation>().CrossFade("Run");//this is later changed to an other animation running left
 
 
         if (Input.GetKey("d"))
             GetComponent<Animation>().CrossFade("Run");//this is later changed to an other animation running Right
     }
 }