I'm not sure how long until it opens, but they're accepting applications for Store Managers right now with a cutoff date of July 11th. I'm guessing end of summer at a minimum. The location is 4405 Concord Pike, Wilmington DE 19803. It's the Concord Square Shopping Center. If you use Google StreetView, it's where the Ace Cleaners used to be.
It'll be nice to have a Warhammer/GW store in GW again. The one in Newark closed a while ago and the one in Philly is grossly inconvenient.