Reading were beaten 3-1 by Tottenham at White Hart Lane on New Year's Day - their eighth defeat in 10 Premier League outings - and remain five points from safety with only 13 on the board from their 21 matches.
Pavel Pogrebnyak had headed the visitors into an early lead, but Spurs then took control and eased to victory thanks to efforts from Michael Dawson, Emmanuel Adebayor and Clint Dempsey.
McDermott has already strengthened his squad with the addition of Sporting Lisbon captain Daniel Carrico, but is keen to do further business in the coming month.
He told Sky Sports: "There is a possibility. We are trying to maybe do two or three players, plus Daniel.
"But you know what January is like, it is never an easy time to get players in. If the deals are right for us and the players are right for us we will be trying to do something."
Carrico is due to arrive at the Madejski Stadium later this week, but McDermott would not be drawn on whether he would make his debut in the FA Cup trip to Crawley on Saturday.
He said: "He should be here on Thursday. I don't know if he will play in the FA Cup. We need to have a look at him in training and assess him and we'll go from there.
"He is a central midfield player or centre-back. He is the ex-Sporting Lisbon captain, he is still young, he is everything that is good about football, he is a good Reading signing, I am sure that he will come in and do well for us."
McDermott was keen to praise the efforts of his current squad in their defeat at White Hart Lane, where Spurs could have won by a greater margin had they taken more of their chances, with Adam Federici's goal being peppered by 34 shots over the 90 minutes.
He said: "This is a really good Tottenham side that Andre has put together here and there won't be too many teams coming here and getting results.
"My players were disciplined and resilient, they have got real great desire and spirit about them. It is a pleasure to work with them day in and day out. If there are any guys you want to be in a fight and a battle with, I am glad I have got these players with me."