The 'require_once' paths at the top of the pages that are in the Admin folder will all begin with:
<?php require_once( "../WA_
If they're in the Admin folder, they have to be looking outside of it for the required files.
So assuming that all of the files and folders that came out of your downloaded PowerStore folder are placed in the same folder on your remote server called 'Shop', then you shouldn't need to change the paths in any of them (I think?). I believe they have their own internal integrity, i.e. are all relative to each other inside the same folder.
The only link(s) you will need to make will be from your (non-store)'s home page to the Shop index.php page (or have your site-root index page redirecting to the Shop/index.php page).
Your WA_Globals looks fine to me . . .