want to run rain water to toilet, how do i do it?

i have 2 toilets in my 1994 build brick veneer house along the outside walls of the house 5 metres apart with a window above it as per diagram below (not to scale). there is a tap at the bottom of the wall above the single row of tiling.

1st question, what is this tap attached to so it doesnt move? a wall stud or something??

2nd questions, i need to run a new copper pipe down the wall to the other side of the toilet with rain water in it, how would i do this? i need to attach another tap to it like the left one. im hoping i can just stick it down the cavity to the side of the window and go from there.

3rd question, i need to attach a second tap to the right hand side of the toilet for the rain water like the left hand one, how do i do that? do i need to knock a hole in the wall to mount the tap then patch it up? or what?

http://www.freeimagehosting.net/uploads/f2b85717cb.jpg


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