Display GUITexture when mouse over object

I am trying to make a png image show on the screen to display which key should be pressed to perform an action such as, open door or pick up object. Essentially I want a GUITexture to appear when the raycast attached to my main camera detects an object or mesh in front of it. I have a js set up that detects when something is in front if my player and set a degbug.log to return the name of bride the object, but I have no idea how to make the gui appear.
Any help at all would be greatly appreciated. Thanks

So, here is an code:

function OnGUI(){
var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
var hit : RaycastHit;
if (Physics.Raycast (ray, hit, 100)) {
  if(hit.collider.CompareTag("Doors")){
DoorsLabel();
  }
 }  
}
function DoorsLabel()
{
GUI.Label(Rect(Screen.width / 2,10,300,300),"Click E to open");
}

Sorry for any language mistake, i polish ;)