Hey,
welcome to flyertalk!
Sorry to read about your problems. It seems you have already contacted the relevant offices (AB, Lost and found), so there is only little hope to retrieve your laptop. You can still try and call the airport police, though, but they will most probably direct you to lost and found. Here are their numbers:
Federal Police at TXL: +49-30-634810,
State Police at TXL: +49-30-634800.
Good luck!