Wilder is looking for reinforcements in defence, and possibly midfield, as he looks to consolidate the club's position in the Premier League during the second half of the season and build on an impressive return to the top flight thus far.
A potential new arrival was being shown around the club's training ground on Monday morning and the PA news agency understands an announcement could even be made later in the day.
Wilder said: "We're still looking. I work with the board and if I don't think players are available or can't get them for financial reasons, then we move on. But we will get one or two in definitely in the next week.
"There's a list of players we're looking at to strengthen for the second part of the season, but if it's not there then we will move on.
"We can't stand still in terms of the group and I'm no different to any manager around the country, I'm looking to improve the players we have and looking to bring more through the door.
"I won't sign players for the sake of it and I treat the club's money as if it was my own."
On the pitch, the Blades host Manchester City at Bramall Lane on Tuesday night and Wilder insists his team will have to be at their best if they are to get anything against the reigning Premier League champions.
Pep Guardiola's side beat United 2-0 in the reverse fixture at the Etihad on December 29 but Wilder was encouraged by his team's display.
"They have been firing on all cylinders recently, but when are they not firing on all cylinders?" said Wilder.
"We'll need to produce one of our best performances of the season to get a result, and our performance at their place last month was excellent – in and out of possession, we had a really good shape and we limited them to very little, which was pleasing.
"The players did a fabulous job and still had a threat going the other way, we got the balance right. We might have to be a bit more adventurous this time because we're at home but nothing is going to change too much.
"We understand the quality they have and we are going to have to play really well but want to make it competitive and be aggressive in our approach.
"We know they will have the ball a lot but I like to think we can cause them a few problems going the other way, like we did at their place."
Wilder will check on the fitness of David McGoldrick ahead of the game. The striker missed the draw at Arsenal with a foot injury and a decision about his involvement will be made on Monday.
Mo Besic is pushing for a starting place after impressing as a substitute in recent matches. It would be the on-loan Everton midfielder's full Premier League debut for the Blades.