Rovers currently sit 13th in the Championship table, but are just five points off the top six entering the international break.
He told the Lancashire Telegraph: "I think we've got to add quality. I know that it's a difficult job to convince players to come to the Championship, maybe from the Premier League.
"But if we can add two quality players to our ranks then I'm sure we can push for promotion. We need a little bit of cover in a couple of positions and it will be up to the manager to decide which positions that need strengthening.
"The competition for places is getting very strong, everyone is coming back to fitness barring a couple, and hopefully we can push on."
Dunn has recently returned from injury.