Is there a way to adjust page width?  In my forum, The actual module extends beyond the borders of the page.

Yes,
you can do this by editing the standard template. The suggested way is to copy the standard template and rename it to something you wish like "my_template"; in this way when you overwrite files for an upgrade, your changes won't be overwritten too.

Editing the template requires some css/html skills and anyway I suggest you to use some tools like firebug for firefox if you are going to customize the css of the template so that you can easily understand what needs to be edited.

bye,
Giovanni.