Once I paused my game how do I bring up a menu?

For my PauseMenu script I’ve put in this:

using UnityEngine;
using System.Collections;

public class PauseMenu : MonoBehaviour {
	public void PauseGame() {
		if(Input.GetKeyUp(KeyCode.Escape)) {
			if(Time.timeScale == 1) {
				Time.timeScale = 0;
			}
			else
			{
				Time.timeScale = 1;
			}
		}
	}

	// Use this for initialization
	void Start () {
	}
	
	// Update is called once per frame
	void Update () {
		PauseGame();
	
	}
}

Now my question is: Once I pressed the Pause key, which is Escape in this script, how do I make a new menu pop up? And also overlapping/removing other GUI formats for a period of time until the Time.timeScale is set to 1 again?

Just displays the GUI at main camera when paused.

function OnGUI () {
    if(Time.timeScale == 0){
        ... draw the buttons as a standard Unity GUI menu ...
    }
}

Example script: http://wiki.unity3d.com/index.php?title=PauseMenu