Your equation gives the natural frequency of the mass-spring system.This is the frequency with which the system oscillates if you displace it from equilibrium and then release it.
The driving frequency is the frequency of an oscillating force applied to the system from an external source. Therefore the driving frequency can be anything you choose; there is no formula or equation for it!
If you start to apply, and then continue to apply, a driving force to your mass-spring system, its motion initially will be the sum of oscillations at its natural frequency and oscillations at the frequency of the driving force. As time goes on the oscillations at the natural frequency will die away (because of damping forces) and only the oscillations at the frequency of the driving force will remain.