Play Animation on Button Press

I have a bit of a problem, im making a mobile touch pad, so when you use the touch pad the walk animation plays.. when your not touching it the idle animation plays, then I added a onGUI button to play attack when pressed but its not working because the other animations come in the way, I cant figure out how to fix it.. any help??

 #pragma strict
 
 @script RequireComponent( CharacterController )
 
 // This script must be attached to a GameObject that has a CharacterController
 var moveTouchPad : EasyMobileJoystick;
 var jumpTouchPad : EasyMobileJoystick;
 
 var forwardSpeed : float = 4;
 var backwardSpeed : float = 4;
 var jumpSpeed : float = 16;
 var inAirMultiplier : float = 0.25;                    // Limiter for ground speed while jumping
 
 var btnTexture : Texture;
 var attack = true;
 
 private var thisTransform : Transform;
 private var character : CharacterController;
 private var velocity : Vector3;                        // Used for continuing momentum while in air
 private var canJump = true;
 
 function Start()
 {
     // Cache component lookup at startup instead of doing this every frame        
     thisTransform = GetComponent( Transform );
     character = GetComponent( CharacterController );    
 
     // Move the character to the correct start position in the level, if one exists
     var spawn = GameObject.Find( "PlayerSpawn" );
     if ( spawn )
         thisTransform.position = spawn.transform.position;
 }
 
 function OnEndGame()
 {
     // Disable joystick when the game ends    
     moveTouchPad.Disable();    
     jumpTouchPad.Disable();    
 
     // Don't allow any more control changes when the game ends
     this.enabled = false;
 }
 
 function Update()
 {
     var movement = Vector3.zero;
 
     // Apply movement from move joystick\
     
     //ATTACK BUTTONS
 
             //
     if ( moveTouchPad.position.x > 0 && attack == true)
      transform.rotation = Quaternion.Euler(0,90,0);
     animation.Play("walk");
     
     if ( moveTouchPad.position.x < 0 && attack == true)
     transform.rotation = Quaternion.Euler(0,-90,0);
     animation.Play("walk");
     
     if ( moveTouchPad.position.x == 0 && attack == true)
     animation.Play("idle");
     
     if ( moveTouchPad.position.x > 0 )
         movement = Vector3.right * forwardSpeed * moveTouchPad.position.x;
     else
         movement = Vector3.right * backwardSpeed * moveTouchPad.position.x;
     
     // Check for jump
     if ( character.isGrounded )
     {        
         
         var jump = false;
         var touchPad = jumpTouchPad;
             
         if ( !touchPad.IsFingerDown() )
             canJump = true;
         
          if ( canJump && touchPad.IsFingerDown() )
          {
              print("Jump pressed");
             jump = true;
             canJump = false;
          }    
         
         if ( jump )
         {
             print("Jump Fired");
             // Apply the current movement to launch velocity        
             velocity = character.velocity;
             velocity.y = jumpSpeed;    
         }
     }
     else
     {            
         // Apply gravity to our velocity to diminish it over time
         velocity.y += Physics.gravity.y * Time.deltaTime;
                 
         // Adjust additional movement while in-air
         movement.x *= inAirMultiplier;
 //        movement.z *= inAirMultiplier;
     }
         
     movement += velocity;    
     movement += Physics.gravity;
     movement *= Time.deltaTime;
     
     // Actually move the character    
     character.Move( movement );
     
     if ( character.isGrounded )
         // Remove any persistent velocity after landing    
         velocity = Vector3.zero;
 }
 
     function OnGUI() {
         if (GUI.Button(Rect(10,10,50,50),btnTexture))
         attack = false;
                 animation.Play("attack");
             }