Unfortunately Lake Murray is about 15 ft down for damn repairs required by the Corp of engineers. That coupled with football season will probably make that weekend one for the fisherman. Lake Lanier is also an option from Augusta.
Bring this thread up a couple of weeks before you are coming in town and I would be glad to show you around if you would like to head up towards Columbia, it's only about and hour drive. Also, if you have never been to Charleston it is an awesome city to visit!!