If you do not have the time, you can assign the work to content writers. Check out http://www.freelancewritingdesk.com. They regularly update my website with fresh content. You can email them with your requirements.
Yes you can find quality writers/writing service at http://www.Elance.com and http://www.Guru.com . Since this is for a website the content have to be seo friendly. Submitinme offers seo content writing at http://www.submitinme.com/seo-writing/seo-writing.aspx