Hello @Behnam ,
nice to hear from you again!
Have you tried http://www.fluechtlinge-willkommen.de
yet? They are especially addressing refugees and try to connect them with locals/WGs. You can register there and hopefully they can help you to find a place to stay.
Feel free to share your experience with that website if you want. I can imagine that this information is useful for others too.
Regarding your search for someone to speak German with:
There is plenty of possibilities to get in contact with native speakers like going to Sprachcafés, sports clubs or something like that.
In Leegebruch there is going to be a festival on next sunday 21st May at Blockhütte Bärenklau in Leegebrucher Chaussee 4, 16727 Oberkrämer between 11-18 o'clock. That seems to be a good event to connect with people since it's organized by a local initiative that wants to welcome refugees. I'm pretty sure you will find people there that can help you with your German.
Check out their website for further information: http://wolv.info
I hope this answer was helpful to you.