The Shakers finished their first term back in League One in a respectable 14th position, but signed off disappointingly with Saturday's 3-0 loss at Stevenage.
And Barker wants a top quality addition in defence, midfielder and attack in order for the club's progress to continue next term.
"I think it's important that we do really improve our squad," he told the Manchester Evening News.
"We've got a good core of players signed up for next year and if we go and get another goalscorer - someone who can get us 20 goals a season - and if we can go and get midfielders that can go and get 10, and get a defender that can stop us conceding an extra 10 goals then we'll be sound."
