Professional developer in order to check and optimize the database and the request made to it from my site. - open to bidding

I have an Article/Content Directory; [login to view URL], for 6 Months an it has 70.000 Articles, 13,000 Authors, 500,000 page views a day and it is growing every day. So, the amount of content is to big in the matter that the database is overloaded and it needed urgent a Professional developer in order to check and optimize the database and the request made to it from my site.