Try

transform.parent.GetComponent<YourComponent> ()

(where, obviously, "YourComponent" is your component). If you want to search from the top down of your object, you can also get

transform.root.GetComponentInChildren<YourComponent> ()

Both "parent" and "root" are members of the Transform class which you should have access to if your class extends MonoBehaviour. The latter would be a pretty intense operation for frame-by-frame updates, but would suffice for caching in Awake()/Start().

Ok, I feel a bit stupid, but it still might not be the best way to do it. But this is how I did it: I have two scripts, WeaponScript and MovementScript, the WeaponScript is in a childHieracy below the MovementScript. So I start out in the MomentScript finding the WeaponScript, then in the WeaponScript I make a function where I can push the MovementScript.

MovementScript takeout:

    void Start()
{
    myWeapon = (WeaponScript)this.GetComponentInChildren<WeaponScript>(); //Here i get the WeaponScript
    myWeapon.setMovementScript(this); //Push this script into the Weaponscript
}

WeaponScript TakeOut:

private MovementScript moveScript; //Makes a MovementScript variable.

public void setMovementScript(MovementScript x) // This is the function called in movementscript.
{
    moveScript = x;
}

I will still absolutely like to hear about alternatives to this way of dooing it, as I am not completly sure this is the best way to do it!