I'm not sure what the exact requirements are for registering with the doctor, we registered as part of the process for our Turkish Driving Licenses and then joined SGK back in 2011 and have been using the family clinic since then for my repeat prescriptions. I'm not sure if you have to have SGK but I think you do need to have a resident permit.
The clinic is in Ciftlik, if you travel through the main road and then take the first right just opposite the chemist, and follow the road up, it is the building after the school. Hope this helps.