A partner with Etihad is not necessarily a partner with VA. I am not up to speed on what is happening with Air Berlin. But I don't think Topbonus is equivalent to Etihad status at all (outside of Etihad anyway). It's a separate program subject to its own rules. Whether or not it says Etihad on the card, it isn't the same as Etihad status. Just forget about Etihad, what you have is Topbonus status and from what I can tell it should still work.

https://topbonus.airberlin.com/web/tb/virgin

VA's homepage won't cover things like this. It's really Topbonus where you need to look. Your question should be to whoever is in charge of Topbonus now: Is the partnership with VA still valid? If the answer is yes, you should get lounge access.