My website history ~ Please give suggestions

Builded on a blogger platform, my website born about 6 months ago. Three months i didn't do any SEO, just posting daily an article. After three months, i go in a easy SEO and after that in some quality blog posts. Then i do a mistake to it when i bought 2 forum blogroll links which gave me a really huge ammount of backlinks. In Google WMT the number is still active (over 180.000) but Ahrefs and Majestic SEO removed 80-90% of that backlinks (because i removed the blogrolls about 2 months ago).
The website runned very well from 1 January to 1 February. (when that bad links still removing on 3rd parties like Ahrefs or Majestic SEO).
Now my website is going down. Two weeks ago, in 5 february i made some changes to my posts. (added some new unique phrases).
In last 3 weeks i did only Private Blog Network posts.
In last couple of days i did some Web 2.0 backlinks with unique articles of 300 words on it, Social Bookmarks, some quality blog comments and daily 5-6 private blog posts with pr 3 and 4.
But my website decreased totally in serpbook although i have made in last days only quality SEO. Traffic is still up (not the one from 1 january to 1 february but its still decent) although main keywords in SERPS are down.
How do you think it will be the future of my website? What i can do? The down of SERPS can be because of a Google Dance because i made a bigger ammount of quality backlinks in last days?