multiply shootforce by fire1 button held?

var crosshairTexture : Texture2D;
var weaponSelect : Texture2D;
var position : Rect;
var position_Select : Rect;
function Start ()
{
        position = Rect( ( Screen.width - crosshairTexture.width ) / 2, ( Screen.height - crosshairTexture.height ) / 2, crosshairTexture.width, crosshairTexture.height );
        position_Select = Rect( ( Screen.width - weaponSelect.width ) / 2, ( Screen.height - weaponSelect.height ) / 2, weaponSelect.width, weaponSelect.height );
}

function OnGUI() // Switch crosshair Texture based on Fire2 down/up state?
{
                if (Input.GetButtonDown("Fire2"))
                {
                        if (position == crosshairTexture)
                                {
                                        GUI.DrawTexture( position_Select, weaponSelect );
                                }
                                else
                                        {
                                                GUI.DrawTexture( position, crosshairTexture );
                                        }
                }
}