Input 3D text with script?

I have a 3D text object called “Menu_Text”, and I’m trying to get it to change when the mouse moves over a plane. This is what I have:

function OnMouseEnter () {
	var textMesh : TextMesh = GameObject.GetComponent("Menu_Text");
	textMesh.text = "Blah";
}

I get this error:

Assets/Scripts/NewBehaviourScript.js(2,44): BCE0020: An instance of type ‘UnityEngine.Component’ is required to access non static member ‘GetComponent’.

I don’t understand?

EDIT

var myClip : AudioClip;
var Message : String;

function OnMouseEnter() {

    audio.PlayOneShot(myClip);
    var Thing : TextMesh = GetComponent("TextMesh");
	Thing.text = Message;
}

This is the script as of now.

You are trying to access the function GetComponent() from the class GameObject. As this is not a static function you need an object of this class to call this function. In short:
Instead of writing GameObject.GetComponent you can just write GetComponent().