Jefferies, who says he also wants to keep his current squad intact, has been working hard behind the scenes to further strengthen his squad but admitted that he had been thwarted on a couple of occasions already.
However, with the transfer window not due to close until the end of August, Jefferies is happy to wait for the right deal and said: "I would like to try and get another couple of players in, I have made inquiries about one or two others but we have not had any success with them.
"But we still have a bit of time. I think we have got a decent squad here, a few players have left since the end of the season, and I want to keep the one that we have got left.
"Obviously every player has their price and if a club comes in and the player says that he wants to move, there's not much I can do about it."
Jefferies was delighted with his new arrivals and insisted that the addition of hitman Kyle won't mean Hearts relying on the long ball next season.
The Tynecastle boss feels that the 6ft 2in striker is just as good with the ball at his feet as he is in the air and continued: "We are looking forward to working with him and we already know all about Kevin Kyle.
"He'll be a real handful. I think that he is coming into his best years right now, when you reach 28, 29 and 30, you're really at the peak of your game because you've already gained a lot of experience.
"Defenders and managers all over the country know about him and hopefully we have players, guys like Andrew Driver, Suso and David Templeton, who can supply him with a lot of top-quality crosses. He's got much more to his game, though, than just getting on the end of balls and scoring goals.
"Our style is not just about lumping the high ball up to the centre forwards and Kevin is very good at holding the ball up, so we'll be looking for him to get the ball down and pass it about like everyone else."