It is about half power steering fluid and half brake fluid. Mechanics are probably out by now, so I am going to have to wait til tomorrow to do anything. But what is going to happen to my car?

 

Pull the rubber return line from the reservoir if possible and cap the fitting that it came off. Now get several QUARTS of trans fluid ( dextron is fine ) and with large bucket under car to catch fluid from from the open return line, start car and start pouring trans fluid into reservoir. If a second person is around who can move steering wheel back and forth that would be better. The idea is to flush out all contaminated fluid, otherwise brake fluid will swell ALL rubber parts in the power steering system and replaceing that can be VERY expensive.

Good luck.
p.s. If car has not been driven then get a turkey baster and suck out as much fluid as possible, then do above.