car back help needed

I have a 2005 reanult senic dynamite megane 7 seater and ive just had it come back from garage and he has told us we need a new clutch as its slipping he reckons 6 months it will last but im wondering will it and also how much will it cost bearing in mind ive already paid out nearly 2000 on the car within 1 year 3 months hekp plz