This sucks. In my opinion, you should be given a replacement car. In fact, i thought they agreed that's what was going to happen? I thought by law if a fault occurs 3 times or more then it's not capable of it's job and a replacement should be issued.
I sympathise with you though, when mine was playing up, it was to and from the dealer, 200 miles each time! Your circumstances are different now, your unborn baby should take priority. If that were me, i would probably ask the dealer to buy the car back off you maybe?