For the promocode problem, try checking out the file
Code:
classes/class_promocode.php
. Unfortunately I am not sure how you'd go about adding in the image of the pet/item...
For the shop page thing, you may be able to do this through phpmyadmin, but I am not sure...I'll be able to help more once I set a shop up...
I don't know for the others (or am too lazy to bother XD)...