"If everything goes well I am convinced we will have a much better team than this year," said Luis Enrique, who refused to name specific targets when asked if AC Milan forward Rafael Leao was on the club's shopping list.
"I am convinced, as much in defence as in attack, in the midfield, tactically, physically," added the former Barcelona and Spain coach.
His comments came after he took Mbappe off with PSG trailing in last week's 1-1 draw against Rennes.
Luis Enrique later said the Ligue 1 leaders needed to become accustomed to life without Mbappe, who recently informed PSG of his decision to leave at the end of the current campaign.
"Sooner or later, when it happens, we are going to have to get used to playing without Kylian," he said after the Rennes game.
PSG are 11 points clear at the top of Ligue 1 before going to Mbappe's former club Monaco on Friday, when they will be without captain Marquinhos due to a calf injury.
They then travel to Spain to face Real Sociedad in the second leg of their Champions League last-16 tie next Tuesday, defending a 2-0 lead from the first meeting.
"Obviously we are entering into a difficult period. The players really want to win things and this is the key point in the season, the best time," the Spaniard said.
"It is all or nothing, and that is a nice feeling."
