I need a social media assistant to post in various sites and respond in my behalf.

I want to post in facebook, twitter, Instagram, pintrest, linkedin, youtube etc. I am looking for an organized social individual to post my messages and carry on my conversations with people, then provide me with a summary of it all on a regular and timely basis. Sometimes it will be a sales post where I am collecting information or asking if people are interested in a product. Mostly it will be keeping in contact with my audience at first and as my audience and business grow and change, so will the job.