I agree that the original steering and seats are pretty bad. You could go for some leather seat covers or some kind of fabric upholstery. You can always check the diameter of your steering wheel and then check for ones you like on the internet or in a physical store. The diameters of the new wheel must be the same as that was given by the manufacturer.
And yes, you can get powered windows installed as MGA.
And yes, you can get powered windows installed as MGA.