Yes, you’d need to change the size of other elements on the page. Depending on the theme, that may not be simple. But as you are using a commercial theme, you’ll need to contact Elegant Themes for help – they provide support for their themes and commercial themes are not supported here.
You could also try using Firebug to help you work with the layout of the page — changing widths and margins. But definitely use a custom CSS option or plug-in as you can really mess things up. Making changes in one element can also affect other templates…like I said, it’s not always simple :).