What am I doing wrong?

I've made a blog about a show called SWAT Kats: The Radical Squadron. I've been struggling with a problem for quite some time, namely the fact that too few people seem to be finding my blog. There are over 40,000 likes for the show on Facebook, but my visitor count seems to be stuck at around 130 per day. I'm trying something to make the blog more interesting. Most of what I post is about getting the show back into production, but recently I've posted some fan art on there to attract fans of the show. I've just started doing this recently, so I don't know whether it will work. But here are some interesting statistics from my blog that suggest it might not:

• By far the most traffic from search engines comes from the same phrase that my blog's title is. My inference: most of the people who come in are regulars and/or people who are specifically looking for my blog.

• The largest entry source comes from Google (see my inference above). My inference: more people use search engines than directly typing the URL into their address bar.

• The second largest entry source is Facebook. I post the most often in one group there. My inference: a good deal of traffic comes from that one group.

Taking all of that into account, my final inference is that most of the people who come in already know about the blog. People who are part of the fandom but don't know about my blog don't make up a large part of the readership. I'm a little stuck as to what I can do to alleviate this situation. I've thought of advertising, but a person talked me out of doing that. His major point being that I need a goal for advertising to be successful. I think I have a goal (it involves a petition, original I know) but I'm not sure about how skeptical people would be towards it (for context, it has a bit over 900 signatures). A good goal would be to get at least 10,000 signatures. If a person doesn't feel like signing it, then I would at least like them to tell other people about it. With any luck the number of signatures plus exposure might help. Any thoughts on what I can do?