How can I make a continue button with the following scripts

Hello I have the question how I can make a continue button that fits in the following script the button needs to be a button when you left a game and then come back again you go to the level were you left and I already created a button so i want that the script fits with the button. These are the scripts were its going about.

 public Canvas quitMenu;
 public Button startText;
 public Button exitText;


 // Use this for initialization
 void Start () {
     quitMenu = quitMenu.GetComponent<Canvas> ();
     startText = startText.GetComponent<Button> ();
     exitText = exitText.GetComponent<Button> ();
     quitMenu.enabled = false;
 }
 public void ExitPress()
 {
     quitMenu.enabled = true;
     startText.enabled = false;
     exitText.enabled = false;
 }
 public void NoPress()
 {
     quitMenu.enabled = false;
     startText.enabled = true;
     exitText.enabled = true;
 }
 public void StartLevel()
 {
     Application.LoadLevel (1);
 }
 public void ExitGame()
 {
     Application.Quit ();
 }

}

and this script

public static int currentLevel = 1;

 void Start ()
 {
     if (PlayerPrefs.GetInt ("Level Completed") > 0) {
         currentLevel = PlayerPrefs.GetInt ("Level Completed");
     } else {
         currentLevel = 0;
     }
 }
 public static void CompleteLevel()
     {
     currentLevel += 1;

     PlayerPrefs.SetInt ("Level Completed", currentLevel);
     PlayerPrefs.GetInt ("Level completed");
     Application.LoadLevel(currentLevel);
 }

}

I hope you can help. Thanks a lot