There are two ways E-V13 could end up in Central Asia:
1- Greco Bactrain Kingdom:
https://en.wikipedia.org/wiki/Greco-Bactrian_Kingdom
In the aftermath of Alexander The Great's death, his vast empire was divided among his generals, one of them, Seleucus Nicator, founded the Seleucid Empire, which controlled most of Alexander's Asian territory, including Central Asia. At a later date, Diodotus, the satrap of Bactria (and probably the surrounding provinces) founded the Greco-Bactrian Kingdom when he seceded from the Seleucid Empire around 250 BC and became King Diodotus I of Bactria.
This kingdom's population did include Greek and Macedonian colonists, soldiers and administrators, as well as natives, so E-V13 could end up in central Asia because of them.
If you test deep subclades of E-V13 and then turn out to cluster in a clade that include people from the Balkans, then you indeed descend from Greek or Macedonian settlers.
2- From Russia :
It is possible that E-V13 could end in central Asia from the time of the Russian Empire or the Soviet Union, I don't know if its possible to determine if this is true, because testing deep subclades that include Russians might also include other people from eastern Europe or the Balkans, in theory it should work but I don't think there are enough samples with detailed subclades, have you joined the E-V13 project or not ? that might help.