goodroi - 3:55 pm on Feb 16, 2012 (gmt 0)
I would not rely too much on those Google searches. Google is notorious for not returning reliable data when doing those special searches. You might want to look at your analytics to see if traffic has actually gone down. If it has gone down, analytics can tell you which specific pages lost traffic so you can focus on them first.
There might be several issues but start with the basics - making sure you have unique & relevant content. If someone is infringing on your copyright you need to defend your site.
Generally I would start with a nice email request before using a DMCA requests.
I would also make sure to use canonical tags and absolute links since some lazy webmasters don't bother removing these items when they steal your content. Going forward when you publish new content make sure you get links to it so Google will crawl it on your site first, before it is republished elsewhere.
When appropriate it might make sense to offer free content to the copyright infringers. I have come across fortune 500 sites that stole my copyright because some intern was lazy. For those rare situations I've paid a writer to create an original article and in return I earned a permanent backlink from a quality relevant site that drove traffic.
As for your link development, I have doubts that you are gaining backlinks with any power. Most directories and press release websites do not significantly help rankings. You can test this by pointing your links at one of your pages and seeing how much (or how little) ranking change there is.