Older house - duct issues - heating suggestions.
I live in Henderson Nevada (Las Vegas) and purchased a home build in 1953. My elderly parents are living in it now. The home looks like it has been added on to at least 3 times. The cooling system is two swamp coolers on the top of the house that apparently have different duct work for different parts of the house. The heating, however, is a single gas wall heater somewhat in the center of the house and needless to say it doesn't heat up the house enough in the winter. I had an HVAC guy come to the house today to see what my options were. After going into the attics, etc. They told me that the swamp coolers should be removed, new heating/cooling unit(s) placed on the top of the house and new duct work run through the house as the old duct work was old, inefficient, leaking, etc. They also said that in some cases holes may need to be punched through the walls so duct work could be run through out, etc.
They also said that they didn't have the staff to do that kind of work and recommended another company. I called that other company and they said they didn't do that kind of work either. I have used the first company mentioned before so I know they wouldn't try to mess with me but now I have a couple of questions:
1) does anyone know who I would need to call to get this duct work stuff done? (like a construction company?)
2) really, I just don't want my parents to be cold this winter, are there other options that I just haven't explored? (They have used the fireplace and electrical heaters but that is lots of work and the electrical furnaces only heat up a small area)
3)(this one is a long shot) - does anyone know of anyone in the Las Vegas, Nevada area that does this kind of work?
Thanks in advance for your helpful ideas.