I just pushed the update for Powerstore 4.5.4 with responsive designs.
This is a free update for any current Powerstore owners. It also fixes installation issues associated with the Apache security mod some users have experienced.
Unfortunately I don't have a demo version available, but as always we offer a 15 day full money back guarantee, so you can download and install it on your local machine to test it out and get a full refund if you aren't satisfied for any reason in that period.