My buddy got me the seed I used, but any ag supply/farmers co-op should have it. It's a prevalent cover crop in MD.
There is a state specification for it. MDOT and the counties buy the stuff for road projects in the fall. Not sure though whether it isn't too late for a cover crop in January. Don't think we would have the soil temp for it to germinate. The contractor should put down these straw mats to control erosion until the spring. Either way, the yard is going to be a mud-bog until June.