Learning Turkish on your own is a do-able, but hard, way to learn the language. First of all, you will need a Turkish-English dictionary. Redhouse is a brand of dictionary that is readily available in Turkey, and also comes in a handy pocket size. It is also reasonably priced. I have seen Turkish-English dictionaries available in most book stores, because Turks are buying them as well for their studies.
If you are looking for a do-it-yourself textbook, it is helpful to have one with explanations in English. I was recommended "Teach Yourself Turkish" as a good choice, and it has served me well. The Turkish textbook I originally tried was much to complicated for me. Be aware that you will not find many Turkish language textbooks with English explanations here in Ankara. You will need to bring it with you or order it from the internet.
Tomer school textbooks are useful as a teaching guide. Even if you have decided not to take a Turkish language class at Tomer, you can pay 50TL for a textbook/workbook package to use at home. The only problem is that the explanations and directions are also in Turkish.