McCulloch has been linked with a return to the Premier League, with the newly promoted Potters said to be interested.
Weir has been offered a new deal but is yet to put pen to paper at Ibrox.
However, Smith said: "The transfer budget is agreed. We have spent a bit and there's a bit left to spend so we are not finished yet.
"But we will not get too many more players, maybe one or two.
"There are two months left of the window so clubs are not inclined to want to sell at this stage.
"If they wait longer they maybe feel there is more financial pressure for the buying club and the price can rise.
"Stoke haven't been in touch for Lee and he is not going to go anywhere, anyway.
"As long as he is happy at Rangers, I am delighted to have him here.
"David Weir's situation should be sorted soon and I'm expecting him to be with us."