Needed vehicle for commuters

Hello dear with motor-talker, in September there is a strong change in my career. my work path will increase from 1km to 38km per track. This is naturally associated with extra costs not to be despised. Currently I drive an A (W176) 180 CDI from the year 2013 which ran about 31,000km. I am looking for a car, which is suitable for this track (almost 100% highway) and very reliable. This should be as cheap as possible in consumption and maintenance and already I could of course also drive the A further, but I guess the costs are so much higher due to the insurance (I’m currently paying an incredible €2000 total!!) and loss of value etc. I’m 22 years old and will earn income of grade A9 (2000 € net after deduction of PKV) at the new job. My hopefully better half earns exactly the same after their studies, but without work. But we like to save untouched in order to build a house in the future. I am bound to the new place at least 5 or more 10 years. What would you recommend me? Continue driving the A180 or sell it and probably even buy a cheaper vehicle under the VKP of the A and if so which one? Thank you in advance!