Firstly I should inform you that you should have married in the embassy of your country; then they would have given you an international marriage certificate. For the current case I could advice you that just go to the Office for Population Registry and Citizenship Affairs in Ankara with your wife/husband and obtain a document evidencing your marriage; then hand that document over your embassy with a letter of petition of yours regarding that you need the int. marriage certificate. They should give it to you...
What is intended with the apostille seal? This seal is granted by a notary but I am not clear about the requirement???
Please note that I am not really sure about the procedures I told you. Now it is too late to call relevant public institutes, I call them tomorrow and will inform you clearly.
By the way, what documents do you have, when did you marry, is the Turkish one your wife or husband, where are you from???
All the best
Ahmet Sirvan KILIC, Attorney at Law
Bar of Istanbul