Children's services in the city have consistently been rated "inadequate" by Ofsted.
Lord Warner was appointed as an independent commissioner last year to oversee attempted improvements.
On Monday the council's cabinet approved plans that will see an extra Â£94m spent over three years.
It includes Â£27.5m already announced for the 2015-16 financial year.
New IT and upgrades to existing systems are also to be introduced, including mobile devices for all social workers.
Under the plans, the number of front-line social worker posts will increase from 511 to almost 600 by March 2017.
The authority has struggled to recruit enough social workers over recent years, particularly those with substantial experience.
Councillor Brigid Jones, in charge of children's services, said the authority had previously relied on "emergency measures" to tackle staff shortages and the latest plan allowed it to approach the matter more "more strategically".
"The biggest thing we need to get right is the recruitment. It's about getting the right staff here and keeping them," she said.
Lord Warner is expected to publish his own report into the state of children's services in Birmingham next month.
Extra social workers and new IT systems are to be introduced in a bid to improve children's social care in Birmingham.