Ok, well, first of all, make advertisements guest-only. Yes, that can be done: General -> Advertisements -> Guest
Yeah well, get a more customized and nicer portal. You also need to edit your theme, some of the text colour clashes with the forum colours too much, and it just doesn't suit it. Take off that xat chat and put it in an external link, and add a customized news box to the portal (meaning, not the forumotions news box, make a custom HTML-coded news box). Add a picture background to add effect to your forum.
Activate your chatbox. I'm serious. Modules -> Chatbox -> Configuration -> Activate -> On -> Display -> Bottom of Home Page
Activate Topic Titles thing. Display -> Structure and Hierarchy -> Show last topic titles on index -> Yes
And this is from memory so excuse me if I made a mistake on where something is. Also your site needs to be more softer on some of the themes (main site), the hard outline of your menus doesn't look very good with the background since it's glaring right out at you.
And well, since I like helping sites...yeah.