Need new car and your advice! Brand, financing etc

Hello, I am “stolze” owner of a Seat Arosa Bj: 2001 with about 90,000km, but unfortunately I don’t know much about cars… I only bought the car for a little over a year and at that time with 76,000km for 2700Euro from the dealer. Now in the near future I need a bigger car for my profession, something like Caddy, Kangoo, Berlingo etc. My Arosa has caused me over 500euro repair costs in the last months and unfortunately also a stone blow in the front window. Since Nov 12 used more petrol than it should, for this an exhaust gas probe was replaced and it went again but since Jan 13 it is back again. I know now certainly that my car is not worth 2700euro anymore. But would I be happy if you could give me an idea how much it is still worth as a private sale? Or if I should give it in payment? From the new car I expect hardly any repair costs for the first years and as said quite a lot of space in the rear area. ken you can recommend here? And what are the advantages and disadvantages of the same. I hope not to spend more than €7000 and make my old one a little bit more money. I want to do something from 2007 or newer with a max of 100,000km. Is that realistic? Besides, what is better private purchase or dealer? As I said, I know only very little about cars. Thank you very much in advance and if you need more information, get in touch! lg peppers180