There is no hoop jumping needed,
Put the PowerStore files on your server at:
and the PowerGallery files at:
There is no re-pathing that will need to be done.
They are 2 separate solutions so are intended to be in separate folders on your site.
Just like you would install Dreamweaver CS3 into a separate folder from Dreamweaver CS4, you should install PowerGallery into a separate folder from PowerStore.