There are lots of great wedding reception sites in Marietta.
Hollycrest Hall is actually on Sewell Mill Road although I don't know how far it is from your ceremony site. Some others in Marietta are (in no particular order):
These are just a few I thought of off the top of my head and found links on AtlantaBridal. If I think of more I will add another post.
I actually had a problem at my own wedding where my original reception site canceled at the last minute so I had to find one that was not very close to my ceremony location. So, I hired a transportation company to shuttle my wedding guests between the ceremony and reception locations. If that is something you would consider, there is a list of Atlanta wedding transportation services here that serve all areas of Atlanta.