Guys - the alternator doesn't "put out" a certain number of amps. The load that's placed on the system determines what the alternator puts out - that is, its output is 'drawn' from it by the load. The system pulls on the alternator, it doesn't 'push' into the system. So, if you have a very tired battery that needs mucho charging, and you have every electrical function in the car turned on (headlights, highbeams, htr/a-c fan on high, electric cooling fans on, stereo on, engine ignition system, fuel pump, rear window defogger, windshield wipers, power windows - etc.) -- you'll be asking the alternator to supply enough current to deal with that. If it can't - doesn't have enough capacity - that's when it also draws on the battery. If it can, it does so and keeps the battery charged up for starts. Overtime, if the net draw is greater than the alternator can put out, it will pull the battery down until you begin to have problems - usually in the form of hard starts.
Don't know what kind of gauge you have in the car - some are ammeters, most are just voltage gauges. The idiot light is usually set up to measure whether the alternator is putting out current. Whether it's putting out enough current to keep up with the demand is another issue.
I would think that your alternator light and voltage gauge should have immediately worked properly upon installing the new alternator - IF a bad alternator is all that was causing your problems. Even if the battery voltage was low, if the alternator was working properly, it should have been putting out around 14.4V right from start up, and of course the ignition system and fuel pump were drawing current from it, as well as recharging the battery. If you cranked it up and the alt. light and gauge were as they were before the install, I think something is still wrong.
And there's absolutely no solution, short of hiring an attorney, to the problem of your wife telling you it's too late and too loud.
