If your lounge access is based on your BE ticket you are not allowed to bring in a guest.
The list of Sky Club and partner lounge locations does not show one in DAR. Perhaps the list is not up to date.
Here is information about lounge locations and access:
http://www.delta.com/traveling_check...ions/index.jsp
Select your basis for access from the drop down menu at the top to see the lounges you can use. Be sure also to scroll all the way to the bottom for additional information, such as the number of guests allowed for different types of access.