Do any of the products have attributes?
You can't get a buy now or add to cart button when a product has attributes; you need to go to the product info page to make choices before adding to cart.
Each kind of listing has its own layout controls.
Your <ul> is using the default "outside" list-style; you can change that to "inside" to move the bullest into the clear.
Add to your stylesheet
#productDescription ul {list-style: inside;}
I posted just a few days ago about changing the all listing descriptions to work similar to the product listing descriptions.
All product listing - moving the description text up?