show guitexture on button click

i have GUI button and GUI texture. when i press gui button i want my guiTexture to show and stay on screen for 3 seconds then disappear. how would i do that with C# in unity? i am making 2D game. i have code for button and C# script code as well.
right now when i click on button guitexture will only stay as long as button is pressed. but i want to stay texture on 3 seconds and then disappear.

using UnityEngine;
using System.Collections;


public class Q3 : MonoBehaviour {
	
	
	public GUISkin skin = null ;
	public GUITexture guiTextureWrong;
	//public Texture2D wronganswer;
	

	void OnGUI () {
		
		
		GUI.skin = skin ;

		guiTextureGun.enabled= false;
		
		//  first button. If it is pressed, Application.Loadlevel (1) will be executed
		if(GUI.Button(new Rect(Screen.width * .05f,Screen.height * .15f,320,100), "Orange")) {
			Application.LoadLevel("");
		}
		
		if(GUI.Button(new Rect(Screen.width * .05f,Screen.height * .45f,320,100), "Apple" )) {
			
			Application.LoadLevel("Question4");
			
		}
		if(GUI.Button(new Rect(Screen.width * .05f,Screen.height * .30f,320,100), "Mango" )) {
			guiTextureWrong.enabled= true;
	
		}
		if(GUI.Button(new Rect(Screen.width * .05f,Screen.height * .60f,320,100), "Banana" )) {
			Application.LoadLevel (""); 
		}
		
		
	}
}

Simple, see my example(write on CSharp):

 private float timetexture = 3.0f;
 private float timing = 0.0f;
 public GUITexture guiTextureWrong;

 void Update() {
  if (guiTextureWrong.enabled) {
   timing = timing - Time.deltaTime;
   if (timing < 0) {
    guiTextureWrong.enabled = false;
    timing = 0.0f;
   }
  }
 }

 void OnGUI() {
 ... 
  if(GUI.Button(new Rect(Screen.width * .05f,Screen.height * .30f,320,100), "Mango" )) {
   guiTextureWrong.enabled= true;
   timing = timetexture;
  }
 ... 
 }