salam,
dear the Vacume cleaner for cars is easily available in market, and its price is about 2.5k-3.5k, i have a Philips vacume and it is best for cars, u can use the ordinary V.C, but it cant clean the corners and conjusted areas, and it also clean the hidden dust in the seats and roof.
And if ur seats and roof is dirty, then take aprox 1 square feet peice of (Cloth Jali) and take i mug water, then add 1 scupe of surf, and 1 spoon Bleach. now shake well until surf disolve, now use that (cloth jali) with that water to remove the stains, it will works. but dont use much water on roof or seats.