You can edit the properties in the css directly.
I think you are trying to change the width? that is on menu.css line 46 and is currently set to 100px.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.