Welcome to the Wefugees Community and thank you for reaching out to us.
We discussed a similar question here before. During the asylum system, you are unfortunately not allowed to leave Germany. Only if you are granted a protection status and you subsequently receive a residence permit, you can travel. For the time being your girlfriend may be able to visit you here?
Sorry that I don't have better news but please don't hesitate to get back to us with any further question.
All the best,