With that much floor below another, it would be cost prohibitive to raise them. You'd spend many thousands and ceilings would probably be too low. When was the house built, sounds like early 70's ranch style, soft contemporary? Some things you have to live with. I raised a porch to be level with a dining room and lowered a deck to make 2 levels, but your project is pretty daunting. Raising toilets, plumbing vents and drains, possibly HVAC. Maybe someone will like your house and you can buy another that is more to your liking.