I wouldn't bother trying to restrict right click (I'm guessing your intention is to try and hide code?).
It never really works, and you'll become quickly frustrated when theres something minor you wish to change and you have to roll back .htaccess changes in order to make it.
Not to mention, with Firefox and Chromes Inspect option, its even easier for people to look into the code behind your site.
Re themes, you can go paid or free. Xenforo comes with a basic theme, and you can start there if you wish.
For aftermarket theme options there are places:
Themehouse.com
DOHThemes.com
PixelExit.com
I am personally using PixelExit themes on my forum and found Russ and Steve incredibly helpful in regards to things. Even if you can't code CSS that well (like me).