[Math] Rotate an Object

I have:

AngularVelocity (seconds)

CurrentRotation (Quarternion)

step (float seconds)

Now I want to calculate how a object with a defined CurrentRotation will be Rotated in step seconds will be

Since I kinda suck at this type of math, can anyone maybee give me a tip how to do this?

Well trying to figure something out, i came to this:

      Quaternion rotation = this.GetCNode().getLocalRotation();
      float[] angles = rotation.toAngles(null);
      Quaternion change = new Quaternion();
      change.fromAngleNormalAxis(Rotationchange.distance(new Vector3f()), Rotationchange);
      float[] anglechange = change.toAngles(null);
      angles[0] = (anglechange[0]/60) + angles[0];
      angles[1] = (anglechange[1]/60) + angles[1];
      angles[2] = (anglechange[2]/60) + angles[2];
      if(angles[0] >= FastMath.HALF_PI){
         angles[0] = angles[0] - FastMath.PI;
      if(angles[0] <= -FastMath.HALF_PI){
         angles[0] = angles[0] + FastMath.PI;
      if(angles[1] >= FastMath.HALF_PI){
         angles[1] = angles[1] - FastMath.PI;
      if(angles[1] <= -FastMath.HALF_PI){
         angles[1] = angles[1] + FastMath.PI;
      if(angles[2] >= FastMath.HALF_PI){
         angles[2] = angles[2] - FastMath.PI;
      if(angles[2] <= -FastMath.HALF_PI){
         angles[2] = angles[2] + FastMath.PI;

This works for like one round, and then the object just stays still.

For unknown reason it seems to be, taht the Angles clamp a litte under FasthMath.HalfPi, :? but I can't find out why.
Any help would be realy nice, and really needed