Image trouble

Hello. I am trying to insert a large image onto my homepage. When I insert an image into a post, the image doesn’t appear on my home page.

Please visit http://www.manzatela.com where I have set the image I want to use as a featured image, in the space I want it to appear. I would like the image to be large and fill the space between the left hand border and the right hand side-bar.

Does anybody know how I can do this?

Many thanks in advance.