Should be something like this:
TiledBackground.y > Self.Height/2 ---- TiledBackground Set y to Self.y - Self.Height/2
When going left x gets smaller, but when going down y gets bigger, so width should be replaced by height and + by - and < by bigger >
I might have done it too fast, so there could be some typing errors, but with the above you should be able to figure it out..