I ran into the same problem you did, a young lady on a different travel site emailed me a Turkish travel agent who bought the domestic Turkish Airline tickets for me for a minimal price. I am out of town and don't think I can find the name of the young man who did this for me before you have to travel, but if you ask around, surely someone on the internet will share the information? Good luck, and enjoy your trip, I envy you, Turkey is so beautiful...I'm pretty sure I got the info from lonely planet thorntree forums, it doesn't hurt to post your request there?