http://tech180.com/600tank/4.jpg
It looks to me like the left chamber is designed to hold a pump and return pipe and the right chamber holds the media. I can't tell exactly from the picture so please let me know if I'm wrong.
You need a 5400gal/hour+ submersible pump to achieve 10x turnover through your filter and it must fit inside the left chamber. You need to measure the chamber and hunt down the right pump. You could alternatively use several smaller pumps, as long as they fit. Run a return pipe from the pump into the tank. Personally I would be going for half that turnover and add a recirculation pump.
I would put a square of egg crate sitting on that lip at the botton of the right chamber and stack nylon pot scrubbers on top. I'd fill most of the chamber with the scrubbies.
I'd put a thin layer of sponge on top of the scrubbies then add any chemical bags (I like biochem Zorb because I hate tannins).
My prefilter would sit on top of the lot where I can get it out easily for cleaning. I'd have a layer of sponge, then felt, and batting on top, like I did here:
How to build a monster mechanical filter box with fine particle remover for under $60
Bear in mind that the water level in the chamber will be lower than the tank when the pump is running, giving you a partial trickle filter effect.
These box filters are old-school but work quite well.
I'm looking forward to that picture - there is something just wrong about making your woman clean your tank