Faulty new 09 car

PLEASE, PLEASE, PLEASE HELP ME.
I bought a car in May 2009 a brand new one directly from the dealer. Within a month had to return the car for a fault with the widescreen trim. This took 3 visits to get it fully repaired. In October got another fault. Told it was due to maintenace has car had a special filter in the exhaust(I was not told when I bought the car). Then same problem plus extra problem, this was fifth visit to get repaired. Then within a week smoke coming from engine and petrol smell in car. Returned for sixth time. I was told leak in pump filter. Wrote them 4 page letter and told them they should replace my car for exact same one or alternative solution. They called yesterday and told me they cant replace the car as they no longer make my model. Saw on their website that they have same car but the higher specification which cost £8000 more than my car. They say can give me guarantee that car will not be faulty again and offer to sit down with me and agree compensation. I dont want as do not feel safe driving the same car.

Alos had prolems with their customer service even made me cry from frustration and anger. In one conversation they tried comparing the car to a ligt bulb.

Bought the car in business name and paid 50% cash the rest was hire purchase agreement to be paid in full within a year. As it stand now we have paid over 75% of the cost of the car.

Can I legally tell them that I dont want the car? I dont even mind paying for the mileage that we have used.

Thank you.

Thank you for your reply Tony.

Spoke to the Cusotmer service manager ar Renault UK and he said they have checked the car and I should drive it for a week and he will call back in a week for us to discuss the performance of the car.

There are saying will not exchange as every faulty as been fixed and car as been checked throughly.

However am sure I can exchange on the basis that I was mis-sold the car. The car has a FAP filter system, which means I need to drive the car for at least 20 minutes at 60mph to clear out the exhaust on a regular basis. and they have confirmed it is not for inner city traffic driving. I was not told this when I bought the car. They have said to go back to the store I bought it from and discuss with them. Surely I can refuse the car on the FAB filter issue as we were not told at point of sale and its a major maintenance of the car. I do not feel its right for me to have to go out of my way to drive just to be clearing out the exhaust system.