At high RPM it's pretty normal for some PS fluid mist to come out of the vent hole in the side of the cap. To keep most of the mist inside I cut off the cotton tip from a Q-tip and stuck it in the vent hole. Give it a try, it work well.
Your PS pump is heading for failure, at high RPM's you are loosing pressure which makes it hard to steer.
You could try to open the pump up, flush it out with gas and see if all of the vanes are clean and free to move in the impeller.
The broken mounting tabs are the result of my water cooled alternator seizing and the belt ripping the pump off. I got a used one for ~$175 iirc, new was $400 at the time.