Putting existing site into wordpress

I have an existing site, http://www.myverdict.net. I want to extend it. I can see the benefits of using wordpress or possibly a CMS system to accomplish what I want but I can’t quite marry the two together.

The site, based on direct democracy, is basically a voting site as it stands.
Users, when registering, have a need to remain anonymous. Therefore no personal info is asked for, not even email. Users are however, asked to select there area of residence. ie:- Country, State, County etc.
Having registered, users are taken to ‘mypage’, which is specific to their area of residence, where they can post questions, arguments, vote and change their vote. These are seperated into international, national, state, county categories and results can also be viewed.
They may also post arguments and vote in areas other than their own. Gross results are shown in the main pages of the site viewable by browsing.
All in all, very like a forum.
In my database I have 244 countries, 3,897 primary divisions and 21,871 secondary divisions, which could equate to categories and sub categories. Because of this, an obvious extension to the site would be country, state and county pages, each containg relevant info.
So my questions are:-
Should I continue with what I’ve got or should I transfer the whole thing into wordpress.
If wordpress is the way to go, how do I set about doing it.
How would you experts go about it. What problems can you envisage. I’ve been pondering on it for a month and cannot get a grip on how to start.