Hi Myriam,
you can try to join one of the groups at meetup.***
****://***.meetup.***/find/language/?allMeetups=false&radius=5&userFreeform=Berlin%2C+Germany&mcName=Berlin%2C+DE&lat=52.516693&lon=13.399994&sort=default
Some of them cost money (I've seen offers of up to 12 € per session), but a lot are for free.
Another oportunity is to go to the HTW (University of Applied Sciences). There you can use the library and the "Mediathek" to learn a language.
****://***.htw-berlin.de/international/unterstuetzung-fuer-gefluechtete/
Here's the link to the mediathek:
****://***.htw-berlin.de/studium/fremdsprachen/mediathek-sprachlabor/
There you can find open hours (Öffnungszeiten) and the address.
It's only in german, which I hope they improve soon.
I hope this helps.