If you need any more Admin help, I can help out, I am an admin on a few wikis, and I could get the navigation bar up to speed, get you a custom logo, and a header graphic, as well as CSS techniques, if you want.
I'm with you there, as an admin on a few communities I've had my fair share of experience with unregistered users. If I were to become an admin, I could set it up so that all users of this wiki would have to login
Take a look at our webinar series -- where you can sign up to interact with Wikia staff, as well as watch past sessions
Be sure to check out Wiki Features to see what features you can enable on your wiki!
Explore our forums on Founder and Admin Central to see what other wiki admins are asking.
Lastly, visit our Help Pages to answer any specific question you may have.
All of the above links are a great place to start exploring Wikia. If you get stuck or have a question you can't find the answer to -- please contact us here. But most importantly, have fun! :)