How to send an express letter from Turkey to Germany

I am currently travelling in Turkey and need to send an express letter to Germany. It needs to be delivered within a couple of weeks or so, not one month, although there is no strict deadline. I want to have some evidence of sending the letter, and, ideally, would like to get a tracking number and be able to track the letter on the Internet. The letter is just a signed paper, not a highly important document like a passport, so I can accept a reasonably small risk of the letter getting lost.

Today I visited a PTT office, but they do not speak English at all. They do not even understand the word "express." I asked them whether they could send my letter via EMS, but they appeared not to know the abbreviation EMS and even asked me what it is.

I know I can use the DHL, but it is expensive (about 45 Euro). They deliver within a couple of business days or so, but I do not need that speed. I just need some cheaper option to send some routine paperwork that is not of great importance or urgency.

Could you tell me some good solution?

If possible, please tell me some Turkish key words that I could show to an officer to make it clear which option I need, as almost no one here speaks English. The closest big city is Bursa.