Ferguson's side suffered relegation from the Championship last season and have subsequently seen star forward Dwight Gayle join Premier League new boys Crystal Palace.
Gayle has yet to be replaced and Ferguson is in the market for extra firepower before the summer transfer window closes.
"We're still hopeful of bringing one or two more into the squad," Ferguson told Sky Sports News. "I do feel that after losing Dwight Gayle we need to replace him.
"We have got strikers at the club and they'll have opportunities, but I do feel if there's the right one out there, we will replace him."
Peterborough start the new campaign at home to Swindon Town on Saturday and Ferguson expects a tough battle in the quest to win promotion back to the second tier.
He said: "We've had a good pre-season, we had a good week in Ireland and the aim is to get out of the league and to win the league.
"We got out of this league twice before, once through the play-offs and once by finishing second, so we've never won the league.
"It's going to be very, very difficult. It's a really difficult league, there's no question about that. It's very competitive, but our aim is to win it.
"It's a big challenge for me as a manager. Obviously, you want to be as high as you can, either as a manager or a player. The Championship is a very, very good league to be involved in, with the big clubs and stadiums.
"This league is different in terms of quality, there's no question about that. That said, it's still a very, very difficult league and the two times we have got out of it, it's been extremely hard and it won't be any different this season.
"I guess a dozen teams would feel like they have got a good chance, so it's a big challenge. We want to get back in the Championship. We enjoyed our time there and I feel we've got a bit to prove to get back in there."