Buying BMW, Audi or Merc doesnt guarantee more reliability........ Just more expense when it does go wrong!
I had the Audi A4 cabriolet and had a similar domino of issues, spent over £3k on 7-8 different issues over 10 months!
Once you get sick of the car........ Sell it.
I would look at a new Focus or Mondeo diesel if i were you?