The two-drachmae coin was struck by King
Kanishka I (c110-130 CE) of the Kushan Empire, located in the environs of northern India/modern Pakistan-Afghanistan. The Kushan kingdom was founded by Heraios, a renegade Greek, and encompassed a wonderful amalgam of Hellenic-Indian-Chinese-what-have-you traditions. This kingdom sounds fascinating, I know close to nothing of it, will look further into it :)
It is quite possible that the decendants of the Kushans are the Kalash, a Hellenic-dialect-speaking pagan people living in the northern Paki/Afghani region who have somehow managed thus far to elude being Islamized by their not-so-friendly neighbors or converted to Christianity by snivelling Greek missionaries who have been pestering them for the past couple of years. It is a shame that these people may inevitably find themselves in the crossfire during the upcoming regional military armaggedon.
The coin itself portrays either Kanishka I or Poseidon
(sources differ) sacrificing over an altar and holding spear or a trident. On the reverse, Goddess Nanaia is "holding short staff tipped by the protome of a horse" according to one source.
P.S. Actually the pic's link is that of a brit coin peddler, and I suspect the Nanaia coin pictured may be still on sale. Check it out :)