Theme not displaying Market Press very nice

I have started to use MarketPress for the first time as I can setup a blog template for store owners to have an almost instant store with a theme I create using Artisteer. However, when I view the store pages, and use the setting in MarketPress to override the CSS, it simply does not produce a nice looking page with the products. One of the reasons I decided it was time to join monthly of WPMU was for the idea I can create stunning looking commerce sites multisite wide, and the CSS option you have would make the stores look great right off the bat.
http://petshop.brickworksmarket.com.au/store/products/test-product/
Here is a simple test theme I have done so I can just see how the store looks with the product. Is there something I must add to my themes created in Artisteer to make this work nicely?

Regards,

Ciaran