how do i do an achievements screen?

in my game level i have 2 scripts that show notifications in game when i collect objects for the achievements.

in the main menu i want a screen that shows the achievements locked until the notification shows in the level.

how do i do this and will this be affected by the fact that when i go back to the main menu the level starts over again losing what i had previously collected.

this is my 2 achievements scripts:

file 1:

 var state:int = 0;
 var scrollSpeed:float = 250;
 var showAchievementTime:float = 5;
 
 private var targetX:float;
 private var outOfScreenX:float;
 private var guitex:GUITexture;
 var edgeMargin:float;
 
 function Start(){
     guitex = GetComponent(GUITexture);
     outOfScreenX = guitex.pixelInset.x;
     targetX = Screen.width - guitex.texture.width - edgeMargin;
     
     yield WaitForSeconds(showAchievementTime);
     state = 1;
     yield WaitForSeconds(showAchievementTime);
     Destroy(gameObject);
 }
 
 function Update () {
     if(state == 0){
         guitex.pixelInset.x = Mathf.MoveTowards(guitex.pixelInset.x, targetX, scrollSpeed * Time.deltaTime);
     }
     else{
         guitex.pixelInset.x = Mathf.MoveTowards(guitex.pixelInset.x, outOfScreenX, scrollSpeed * Time.deltaTime);
     }
 }

File 2:

 var FirstKeyTex:Texture;
 var FifthKeyTex:Texture;
 var TenthKeyTex:Texture;
 var FirstStepTex:Texture;
 
 private var firstStepTaken:boolean;
 private var keys:int;
 var edgeMargin;
 
 function Start(){
     edgeMargin = Screen.width * .01;
 }
 
 function playerMoved(){
     if(!firstStepTaken){
         unlockAchievement(FirstStepTex);
         firstStepTaken = true;
     }
 }
 
 function pickedUpKey(){
     keys++;
     switch(keys){
         case 1: unlockAchievement(FirstKeyTex); break;
         case 5: unlockAchievement(FifthKeyTex); break;
         case 10: unlockAchievement(TenthKeyTex); break;
     }
 }
 
 function unlockAchievement(achievementTex:Texture){
     var go:GameObject = new GameObject("Achievement Object");
     go.transform.position = Vector3(0,0,Time.time);
     go.transform.localScale = Vector3(0,0,0);
     var guitex:GUITexture = go.AddComponent(GUITexture);
     guitex.texture = achievementTex;
     guitex.pixelInset.width = achievementTex.width;
     guitex.pixelInset.height = achievementTex.height;
     guitex.pixelInset.x = Screen.width * 1.1;
     guitex.pixelInset.y = Screen.height - achievementTex.height - edgeMargin;
     var achievementScript:AchievementScript = go.AddComponent(AchievementScript);
     achievementScript.edgeMargin = edgeMargin;
 }