All that you mentioned will work, but I'm a little leary using acetone on my paint..I realize that its only one third, but still its a potent chemical.
If it's raining and you have to go somewhere, where do you put that wet car cover? And to answer your question..I live in a Condo and almost everybody who gets a new car will buy a car cover and it may last a month or two.
Hope the Mrs. gets well soon.
Isn 't there a filter for the heater? Or is the heater fan blowing the dust around? As oneheadlite suggested, perhaps ducting should help.