Type A is Not Necessary
Type A transmission fluid isn't required in your Tomos. You can use a regular Dexron / Mercon / Universal ATF without issues. You can also use 10w30 motor oil if you'd like. Don't think it's the end of the world if you can't find type a fluid near where you live. In fact, you should never go out of your way to find it. As long as you change your oil regularly, and put the correct fluid amount in, you will be fine. Some people even mix up gear oil with transmission fluid for a performance oil mixture in their Tomos.
Type A ATF fluid, where to find
If you have a Mercedes Benz dealer in your area, you can find Type A ATF there, as old Mercedes passenger cars transmissions use Type A fluid only. Part number is #A 000 989 26 03, and you will probably end up with a Shell Donax TM Type A one liter bottle. NB: Very expensive by the way.
At Dollardays, they sell Type A fluid in cases of 12 bottles, more than you will ever need for your Tomos moped lifespan. If you want to order Type A fluid online, here is the URL.
One can find Type A in the automotive section in many grocery stores, at some discount stores and dollar stores.
The next closest thing to Type A ATF fluid is Universal Tractor Fluid (UTF), designed for wet brakes applications on farm tractors. Many old tractors recommended Type A fluid and it cross-references to UTF.
You can find UTF at Wal-Mart (Supertech 2000 Tractor Fluid) and many farm supply stores. Mobil 424 is also a good brand of UTF. I have used it in my A55 and works fine, and dont forget to put a John Deere bumper sticker on your Tomos!!! :-)