Benitez - who wants to strengthen a number of key positions for the second half of the Premier League campaign - had been looking for United to do its business by January 20.
"I talk to Lee Charnley everyday, but no idea (on any budget) but still working".
He said to BBC Sport: "Newcastle boss Rafael Benitez is still trying to bring players in - but might have to face up to the fact that this is going to be a frustrating month for him and just get on with things".
With 11 days gone, Benitez's confidence is ebbing away.
Newcastle would only have to pay a compensation fee to Toure's BSC Young Boys, as he's yet to sign a professional deal, and this signing would certainly be one for the future rather than providing an immediate boost to Benitez's attacking ranks. But we do not want to sell anyone who will add value to the team and we can not loan out players if we do not have options to replace them'.
Swansea will arrive with manager Carlos Carvalhal unbeaten as a manager at St James' Park, sealing 1-0 wins there with Sheffield Wednesday in both 2015 and 2016.
Liverpool pose test of City's bid for immortality
They will be hoping that the arrival of new defender, Virgil van Dijk will help stop Pep Guardiola's irresistible frontline. Jurgen Klopp's team parted with a world-record £75 million fee to lure the Netherlands global away from St Mary's.
Newcastle are 13th in the division ahead of this afternoon's home game against basement club Swansea City.
Relegation rivals West Ham have an interest in Jonjo Shelvey, but the Magpies boss has ruled out letting any player go who has a part to play on the pitch. The 57-year-old has been reluctant to talk about the transfer window in his recent press conferences, though that position could change. I have heard people talking about our players, but we do not have any offers.
He said: "We are clever enough to understand the difference is still very small in terms of points".
Meanwhile, Newcastle are continuing their investigation into allegations of bullying and racism made against Under-23 coach Peter Beardsley.