Dempsey's goals along with a Damien Duff effort helped Martin Jol's side to a 4-0 triumph in a London derby in which the npower League One leaders' performance belied the scoreline.
"It was good for us to get the win," Dempsey said after the match.
"It's the first time I have got a hat-trick in my professional career so that was good as well.
"Hopefully we can go on a nice run in the FA Cup and keep doing well this season.
"You have to take one game at a time.
"It's the luck of the draw so it depends on what teams you get and whether you are playing home or away. That comes into it.
"What will be will be. We will just take it one game at a time and, if we play the football we know we are capable of, maybe we can go all the way."