Australian Passport holder

I will be travelling in a group doing an overland trip Istanbul to Singapore over 7 months, the amount of time between departure from Australia and arrival in China does not allow me to arrange a visa in Australia prior to my departure, I plan on being in Istanbul for 30 days prior to the start of the tour. I will not have Turkish paperwork as a visa is not required for Australia citizens. Please advise how I can arrange a visa whilst in either Istanbul or Ankara. Thank you. Tina