From looking at the manual, I can see the AVR 4500 doesn't have any HDMI inputs so your best bet is to connect the Panasonic DMR-EX78 direct into the TV via HDMI and then connect an optical cable from the Panny to the AVR 4500 for sound. The PS3 would connect in exactly the same way with the same leads to both.
For speaker height, you ideally want the fronts to have their tweeter at your ear level and the centre is normally placed under the TV, though could be placed above it on a rigid shelf. Surrounds the same if possible, but could be wall mounted higher and angled down if this isn't possible.