GUI SpaceShip Movement Problem!!! Please help!!

using UnityEngine;
using System.Collections;

public class simpleMovement : MonoBehaviour 

	public float speed = 0.00f;
	public float rotSpeed = 10.0f;
	public float strafeSpeed =10.0f;
	private float engineSpeed = 0.0f;
	public float pitchConstant = 1.0f;
	public float yawConstant = 0.0f;
	public GameObject boostersprefab;
	public GameObject boosterPos;
	private GameObject instantiated;
    private bool instanBoostersExist;		
	// GUI texture
	public GUITexture forwardPitchButton;
	public GUITexture backwardPitchButton;
	public GUITexture leftPitchButton;
	public GUITexture rightPitchButton;		
	// Booster Start Function
	void boostersStart()		
        if(instanBoostersExist == false)	
		  instantiated = (GameObject)Instantiate(boostersprefab, boosterPos.transform.position, boosterPos.transform.rotation);
		  instantiated.transform.parent	= boosterPos.transform;
		  instanBoostersExist = true;			
	// Booster Stop Function
	void boosterStop()
	    if (instanBoostersExist == true)
		    instanBoostersExist = false;
	void Update()
	// Axis Declaration	
	float pitch = Input.GetAxis("Pitch")*pitchConstant; 		
	float yaw   = Input.GetAxis  ("Yaw")*yawConstant;		
	float roll =  Input.GetAxis ("Roll");
	float gas =   Input.GetAxis ("Gas");		
	Vector3 strafe = new Vector3 (Input.GetAxis("Horizontal")*strafeSpeed*Time.deltaTime,Input.GetAxis("Vertical")*strafeSpeed*Time.deltaTime,0);		
		// Engine Mechanism		
		 if (engineSpeed <10 && engineSpeed > -3)
		  engineSpeed += gas;			
		 if(engineSpeed > 10)
		  engineSpeed = (9.99f);	
		 if (engineSpeed<-3)
		  engineSpeed = (-2.99f);		
	      else if(Input.GetKey("z"))// Brake
		  engineSpeed = (0.00f);
	// SpaceShip Physics Movement

How do I use the GUI button press (already I have tried some ways, but am not able to achieve the effect) which is been assigned with respective texture to move the ship in yaw and pitch position. I have found the way to achieve this using keyboard controls, Please some one help me to fix this code for GUI texture. Thanks a lot, If you can please explain a bit, It would be of immense help. Thanks

You created two exact questions from the look of it, answered the other.