Despite bringing in Wayne Bridge, Royston Drenthe and Danny Williams already, Adkins has seen many targets move elsewhere in what is turning into a frustrating summer for the 48-year-old.
The Royals manager has admitted that some deals he thought were concluded had fallen through at the last minute and says he expects a busy few days ahead as he looks to bolster his squad.
"There are three positions I would like to strengthen," he is quoted as saying by Get Reading.
"We've still got a few days left and a lot of business is done in that time.
"I still like to think we are going to improve the group."
His main priority this summer was to bring in a striker but saw targets Gary Hooper and Charlie Austin move to Norwich City and Queens Park Rangers respectively.
Adkins admits he would have preferred to get his transfer activity finished early this summer but understands that getting deals over the line is never that easy.
He said: "You have to understand what goes on behind the scenes.
"Maybe there are one or two deals that we had done that have fallen down for one reason or another, but you keep them private."