Removing the empty space in product listing view

http://jeffdavidcasting.com/catalog/index.php?main_page=index&cPath=37

You see that empty space before the right border? I would like to have a product in its place.

How can I do so?

turn off the right column in the admin>configuration>layout settings

Okay I assume. I change the column layout, but I want to have this view: http://jeffdavidcasting.com/catalog/index.php?main_page=product_info&cPath=37&products_id=7 on individual products.

There are switches built into the code that allow you to do this kind of thing easily.

Look at /includes/templates/your_template/common/tpl_main_page.php. The comments at the top describe several different ways of having things like the right column appear or not appear on any given page. They require a little bit of code writing, but you just have to follow the examples.

So you can use a switch that shows the right column only on the product info pages.