Steve McClaren says it is vital that QPR bring in players before the loan window closes at the end of this month.
German defender Toni Leistner is the only senior player signed by Rangers so far this summer.
And McClaren, whose first game as Rangers manager ended in a 1-0 defeat at Preston, believes the shortcomings that were evident last season will continue unless new faces arrive.
He explained: “We’ve brought in one player and things from last season – seven clean sheets and three away wins – are still going to be there.
“We’ve made one signing. I think we need more and we’re still searching for that.
“There’s a few weeks to go before the end of the loan window and I think we will be looking to strengthen the squad.
“How we do that will go a long way to say how we’re going to do this season.”
McClaren fielded a young side at Preston, where Rangers were second best for most of the game.
“You don’t really know what you have until the first game and now we have a better picture of what we need to do,” he said.