wow, 200 articles and 5-10 UV daily ? and they all are copyscape-passed ?
Have you check the on site part? and perhaps the domain history?
IMO there's something really not right on your on-site, not the backlinks and off-site stuffs.
your article directory source sucks
post on different article directories so you can have more intern traffic
create a couple of web 2.0 a week with original content and linking to other authority sites at the same time
buy a couple of likes or tweets on fiverr to get social signals
I can assure you if you will start building social signals to those 20 articles of yours you will get huge changes in both traffic and rankings.