MarketPress: Shopping Cart Layout Design

How can I change the layout of the Shopping Cart Page. I'm running into a few problems with Marketpress and need to fix as soon as possible with a cleaner look.

Problem is that Shopping Cart Page fields seem to run together. Would be nice to even add borders to get a cleaner look.

What files and what type of code do I need to adjust to accomplish this task.

weblink is just add something to the cart and when you go to checkout you will see what I'm talking about. Need more space between certain items etc...

Thanks In Advance!