The Rs remained rooted to the foot of the Championship table following Wednesday's heavy defeat at Layer Road which came just 48 hours after Harford was placed in temporary charge following the sacking of John Gregory.
"It was a very, very open game and end-to-end defensively," he said.
"But we're very short at the back at the moment and we're leaking goals for fun. We have to do something about that."
Former Premier League managers Stuart Pearce and Glenn Roeder have both been linked with the managerial vacancy at Loftus Road.