You should try contacting Advertising.com or FastClick.com
They both are respected among site owners with traffic like yours and optimize served ads based on your web traffic profiles.
Have you tried PR to build traffic? Like the Howard Stern Show?
Since yesterday I'm getting about 500 users per day on my MarriedByAmerica site, if you would like to comment on the show and post a link to your site in the forum please feel free to do so
http://www.marriedbyamerica.us
Or, please contact me by e-mail about trading homepage links.