If you have a own Facebook Fanpage - no Group! you can increase your likes with a little trick.
Use facebook with your site account, not with your normal admin name.
Go to different other facebook pages related to your own topic and like the fanpage.
Now like the single posts from the different posters / commenters too.
The members who posted anything will now see on their own status site, that you like their posts and the most of them will visit your site to see who you are.
Some of them will walk away and some of them will like your site too.
Test it....