Turn off water main, then cut plumbing back to general area of new holes. Remove excess pipe sections.
To re-route the supply lines, first clean all of the fittings with a wire pipe brush (Image 1). Add flux to the ends and assemble the section of pipe that turns upward toward the tub.
Sweat the fitting for the end of the vertical supply line (Image 2), then insert into the elbow added to the end of the existing run (Image 3).
Wedge a piece of pipe underneath the new one to hold steady, then sweat the remaining joints.
Set the drain line to its new location by applying PVC pipe cleaner, followed by glue to the outside of the pipe and the inside of the reducer fitting (Image 4). Add an elbow, then build the "P" trap.
Add the last piece -- the vertical pipe that will connect at the hole and screw onto the extension tube from the bathtub drain.