I would agree with the last post, the code is very bad and while the site may have some features you like, the site itself is poorly laid out. I would suggest that you use a system called
Joomla. Its a very powerful database driven system that does not require you to know lots of code, or any code for that matter and allows a virtually unlimited amount of customization. In fact I recently found an ad on to a component that allows for a customer to design custom shirts in the shopping cart system called
VirtueMart which is a free shopping cart system. I use Joomla for all my sites and as a developer of code for my site I can say that its by far the best open source and Free website builder system in the world. Plus there are thousands of free templates, and about as many really nice low cost ones too. Best part is that its all server side built and managed so you dont need anything other than your browser to make it.