Build and promote company profile on social sites

Our company needs to build and maintain a presence on social media sites like facebook, twitter, linkedin, pinterest, etc. We are looking for someone who has the requisite experience and is adept at: 1. building and maintaining the social sites (twitter/facebook/pinterest/google+ and upto 5 other sites) as well as manage user comments on the companies blog 2. promoting businesses on these sites [login to view URL] the users one should engage with 4. engaging with users effectively 5. building a large followers count (actual followers not "fake bot followers") We can start off on a trial basis for 15 days and then on a monthly retainer. The project cost is indicative only of the trial.