How can i access in a prefab a variable from a gameObject?

Hi guys,

i instantiate a gameObject every few seconds. In the attached script i want to use a variable from a Gameobject (which is not a prefab). This means, the variables should be the same in every created clone.

How to Access the variable?

Script which is attached to prefab:

public GameController gameController;

	void Update()
	{
		float variable = gameController.gameSpeed;
	}

Script attached to gameObject:

public float gameSpeed;

	void Update ()
	{
		gameSpeed = gameSpeed + 0.1f;
	}

Normally i attach the Gameobject to the prefab in the Inspector, but it is not even possible.
So what am i doing wrong here?

found a solution finally, just had to add this Code to the prefab:

GameObject gameControllerObject = GameObject.Find ("GameController");
		if (gameControllerObject != null)
		{
			gameController = gameControllerObject.GetComponent <GameController>();
		}

i searched for the wrong gameObject, that was my big misttake^^