Wolves dropped into the bottom three for the first time this season after losing at home to Aston Villa on Saturday.
McCarthy retains the support of club owner Steve Morgan, and said: "If there was a player there for us to sign, and it's one we can do, then he (owner Steve Morgan) would be supportive. But it is difficult to get anyone - and particularly anyone who fits straight into the team."
He added: "Trying to get someone in, who has been in an around the Premier League and understands it, is very hard.
"There is nothing imminent but we will keep on trying. It's got to be someone who will improve the team, not just to fill up the squad."
McCarthy has given his support to former skipper Karl Henry who has apologised for his sending off against Aston Villa.
Midfielder Henry will be banned for three games after aiming a kick at Villa winger Marc Albrighton and receiving a straight red card.
McCarthy said: "There is no excuse for it and Karl gets a kick up the backside for doing it. He's apologised to me and the players.
"But he hasn't made many mistakes in the last five and a half years at Wolves and has been brilliant for this club. He gets my support for the next 13 games he will be available for."