If you want a custom Trulia description, list with an agent who pays to be a PRO on Trulia.... Your agent can change and enhance the description plus add an unlimited amount of pictures. I'm not in GA but for an example, check out my listing at 1904 Spanish Bay Ct in Raleigh, NC. Zillow descriptions from an agent feed directly off the the MLS so will not allow an agent to make a change as every night they revert back to the MLS description.
If you are a for sale by owner, the post is not allowed, you can however try blogging about the property; if and when you do list with an agent, he/she can post it for you, ask, or consider any flat fee realty company that feeds into the site.