Webcomic not converting

I'd really appreciate some advice on how to make this site perform better.

http://www.hockeyzombie.com/

I'm not the webcomic artist, but I do the hosting and website design. Last week I redesigned the site and put up some ads to try to cover our bandwidth costs, but the ads aren't converting at all. So far this week there have been over 26k adsense impressions but only 4 clicks. These ads are only on the main site, not on the forums.

I installed phpAdsNew so that I could rotate Adsense styles and figure out which converts the best. One is a default, the others are various bordered/unbordered blends into the page. Part of the time I'm swapping them with CJ ads to investigate the affiliate marketing route.

Possible problems I see:
1. Ad content.
All I get is advertisements for other web comics, and I get the same few ads over and over. Most of my content is in imagery, which isn't good news for Adsense when they're trying to figure out what ads to place. I've added the <!-- google_ad_section_start --> and <!-- google_ad_section_end --> around the main news posts, but it will take a little while for them to take effect, and the artist isn't greatly verbose at the best of times.
Over 80% of the traffic is from returning users, who will visit 4 pages on average each time they visit. The new visitors will each check out 13 pages on average. I've only seen 6-7 different advertisers for my site's content, so my users keep seeing the same (uninteresting) stuff over and over.


2. Ad position.
The ads are in the typical advertising locations and become victims of ad blindness. I think the idea place would be just above the comic box or above the news posts, but those are off limits because they're too intrusive to the content.

3. Demographics.
Approximately 60% of the viewers use Firefox and probably can't see the ads. I understand that adblock doesn't stop the ads from loading, but only from rendering. So false impressions are probably being created, but this is the case with any site I guess. I'm worried it might be a little more adblocking than the average site gets, though. Is my phpAdsNew software and the positioned DIVs in addition to the advertises causing more adblocking than is necessary?

My CJ ads seem to get a better CTR, but not by much. I'm considering Chitika ads, as well, since I can customize the products that I am advertising and still get paid CPC. I know that with the kind of traffic the site is getting, it should be able to perform better. I'm not looking to make money from this enterprise, but it'd be nice to recoup bandwidth and have extra capital to buy some advertising on another comic.

If you read to the end of all that, then you have my thanks. What advice do you have?