Welcome to United Bimmer.
Let's start with the coolant. It's obviously leaking, but from where? Hoses, radiator or expansion tank? Finding that out determines what needs replacement. With your car running take a newspaper (a thin one) and roll it up. Take rolled up newspaper and while your engine fan is spinning gently touchtw newspaper into the fan. The idea is that if the newspaper stops the fan your fan clutch has gone bad and you need to replace it. When it goes bad the fan cant pull enough air into the engine to cool it properly.
As for the windows, when you hit the switch can you hear the motor inside the door?