I have a beige carpet in my living room which is quite grubby in places. The carpet is at least seven years old but I can't afford to buy a new one at present. I've had the room painted and want to make the carpet look good without spending too much money. I have a vax cleaner and have used it regularly over the last two years. Judging by the colour of the water when I empty it, it picks up quite a lot of dirt, although the carpet still looks grubby in places afterwards. Would a rug doctor or professional cleaner make it look any better? How much would it cost? Any other suggestions?