By putting the jump leads on the wrong polarity you have most probably fried the electrics. On a car of that age it will cost more to repair than the car is worth. Just get the local scrappy to collect it if it's not insured. Then buy another cheap car, there are plenty about, but I warn you not to buy a Renault again as the electrics are not very reliable as they get older, in fact there like that from new.
DB
July 2011