The club has so far made just two signings ahead of the new season.
Curtis admits he has been frustrated by the club's summer transfer dealings so far
With the start of the new Premier League season just two weeks away, Swansea have made just three signings so far this summer, bringing in midfielder Leroy Fer, Dutch centre-back Mike van der Hoorn, and goalkeeper Mark Birighitti.
However, attempts to increase the number of new recruits have so far been fruitless, with the Welsh side recently beaten by Stoke City in the race for Liverpool midfielder Joe Allen, while the departure of Bafetimbi Gomis to Marseille has left the club in the market for a striker.
Leicester City's Leonardo Ulloa and Sevilla's Fernando Llorente have both been mentioned as possibilities, but Curtis admits that more progress needs to be made in order to ensure the squad is able to compete and steer clear of a relegation battle next term.
He told the BBC: "I think there is a lot of frustration, with the supporters but also with the players and maybe the board themselves. We all know there is a need for us to bring people in now.
"There is two weeks to go now before the season starts and hopefully before the start of the season, of the players we are looking to bring in, someone will come through the door.
"We are aware of things going on, but not the details, that is with the chairman. It is time now to get a big signing in just to give everyone a big lift. It has been obvious to everyone and apparent that we need to strengthen up front."
The need for a new striker looks set to grow on the back of growing reports that Andre Ayew is poised to leave the club, with Sky Sports claiming he has attracted the interest of West Ham United.