A quick overview.
Needs a new skin. The current skin looks to plain also it looks a little common. The logo and logo text do not look that great, you can find some nice themes for phpBB3 forums here /www.rockettheme.com/.
You also do not have a lot of forums, maybe some sub-forums would help your site look more appealing to users as it will identify certain topics, Just browse this forum and take some tips on how you should possibly format your forum.
Increasing traffic is really hard just make sure your on all major search engines, make sure you keep advertising on forums like Admin Community. Remember it can take years for a site to build up its reputation and get a lot of traffic. Also maybe post videos on youtube about your site, create a Facebook & Twitter page, Just try your hardest to get the sites name out there.
If you fix these things Im sure your forum will become a better place, best of luck!