I did a few test runs with Facebook ads and came to a conclusion. Unless you have an ad that makes people go crazy and feel they must go to your site, they wont go. It was almost decent when getting likes for a facebook page, but that's about it. But, that's just my foray into FB ads. Results may vary with everyone.
I like how facebook deploys their ads, I am going to be starting some big campaigns with google and facebook ads but I think I might actually prefer facebook's way of doing ads. For one they target a specific audience(google tries to do this but often times are less successful) and you know what website your ads will be placed on.
We have run Facebook ads in the past for my Doberman Board. without much luck.. We personally do better with Ad Words.. I suspect that with your type of forum being location based you could have much better luck.
You say it's not great Peggy - but if you are living in those areas or otherwise have an interest in them, it does the job you want it to. Too many people get wrapped up in trying to make fancy sounding adverts - but a direct, down to earth one can work a lot better for most campaigns.
I've never used FB ads, I take it you'll be able to target this just to people in your geographical area?