Saw your other post on the cost of recovering seats where DanTwoLakes responded. Yank the carpet and see if you can get it clean, if not, go with his vendor suggestion. He truly is an expert of his craft and knows what he's talking about.
As far as seats, I'd be looking through craigslist or the local salvage yards for a better set. Don't spend the money recovering the seats because you'll never get back the investment in the end.
As long as the paint is sound, I'd personally just leave it. You're just going to hurt the value of the car when the door jambs and under hood don't match. Just make it nice and enjoy it, or make it nice and sell it. Low mileage cars like that can fetch a decent price with little hassle.