Ahhh. I'm the creator of the CG-Amazon script. I'm not sure I see what you are trying to do. You have a store script already, how do you want to tie in things?
You'll likely have to talk to the creator of WP-Amazon, as I don't know how it works.
CG-Amazon has sample scripts for browsing through products, but it isn't the 'grab and display everything amazon has' type of script. You'd pick selected products and 'cache' them locally, enabling you to add annotations and further tie in with WP.
But I've got little interest in trying to tie in with yet-another script at this point. If anything, I'm going to build out the CG-Amazon capabilities so you can just 'turn on' a store page at any point you want one... ;)