Increasing Traffic to Business Directory Website

We have a Business directory and recently the traffic to same has vanished, we were wondering if someone could help us get back the traffic. We have been following WebMaster World, and a lot of site has been affected from 1st week of September. Now, we have been using and Sitemaps and are using pretty fast servers (the site speed by google comes out around 90 in average) We are looking for someone, who could give us insight and ways to help us get back. Please do not bid, if the credentials and experience do not show that you would have done this kind of work before. As we are looking at advice, we would implement based on recommendations to see the changes and if the results are encouraging, we would not mind retaining your services on monthly basis for a fee.