Fast train from PVG to Shanghai for 6 hour layover sight seeing and return

We'll be arriving at PVG (on domestic flight from Zhengzhou) on Wednesday 9th May 1.40pm
NB: we understand our luggage will be checked all the way through to our final destination (Bris).
We do not need to be back at PVG until 8pm on the same day - for our international flight back to Brisbane.
Could you please detail which train / station / platform we should go to in order to take the fast (Maglev) train from PVG to SH to do some sightseeing .... and then guide us to which train / station / platform we should take to get us back to PVG by 8pm.
Any known costings would also be valuable information.
Very much appreciated,
Sue