Level completed but still playable (timescale problem)

I'm working on a game in which, after you complete a level, a GUI box (called in onGUI) pops up showing you the score, and a few options. That all works great.

The problem here is, when I finish the level, I am still able to move my character around and play as though nothing happened.

The way to fix this which I thought was, that I could add Time.timescale = 0; at the place where I check if you completed the level or no. But this method didn't work, as when the next level is loaded, or when any of the options are chosen, the timescale doesn't return to 1.

I tried putting time.timescale = 1, whenever you click on an option, but still no use.

Here is my code:

 void OnGUI()
     {
         PlayerPrefs.SetInt("levellock" + (currlevel), 1);
         if(levelcomplete)
             {
             Time.timeScale = 0;
             GUI.Box (new Rect (Screen.width*1/8,Screen.height*1/8,Screen.width*3/4,Screen.height*10/14),congobase);
                 
                 //Go to next level
                 if (GUI.Button (new Rect (Screen.width*7/20,Screen.height*3/8 ,Screen.width/3 ,Screen.height/8),gonextLevel)) 
                 {
                     Time.timeScale = 1;
                     Application.LoadLevel(currlevel+1);
                     print("next level");
                 }
             
                 //Go to Level Selection menu
                 if (GUI.Button (new Rect (Screen.width*7/20,Screen.height*4/8 ,Screen.width/3 ,Screen.height/8),golevelSelect)) 
                 {
                     Time.timeScale = 1;
                     Application.LoadLevel(0);
                     print("level select");
                 }
             
                 //Play this level again/Refresh
                 if (GUI.Button (new Rect (Screen.width*7/20,Screen.height*5/8 ,Screen.width/3 ,Screen.height/8),doRefresh)) 
                 {
                     Time.timeScale = 1;
                     Application.LoadLevel(currlevel);
                 }

Basically what I want is, the game to pause when the menu overlay comes up, and the next level to load smoothly as it should load normally.