After the 1st of August, you can also apply for a visa for family reunification to Germany, if your family member has only subsidiary protection (that means his/her residence permit is only valid for one year and then can be renewed for another two years). Before applying you need to ask for an appointment with the German embassy in the country where you are staying at the moment. You can already now ask for an appointment under the following website.
The page is unfortunately only in German and English. If you need help with filling the fields, it might be best if your family member in Germany goes to a social worker from Caritas, Diakonie or AWO and gets assistance there. Please keep in mind, that there will be only 1000 visas per month issued for family members of beneficiaries of subsidiary protection in Germany. For more information about the requirements, please have a look at a post we did in May.
It is so far unclear if visas will also be issued if you apply in Greece for a visa to a family member with subsidiary protection in Germany. According to an employee of the German embassy in Athens, it is possible to apply for a visa. But what will happen with the application is so far unclear.