After a wee bit of digging around, I discovered these coordinates on Wikipedia: 45°40.8′N 6°53′E

I know nowt about GPS - is that relevant?

THEN... I found this:
http://local.live.com/default.aspx?v=2&style=h&lvl=16&sp=Point.45.68_6.883333_mountain___

Looks pretty close to me!

The coordinates could be for the stone column (in it's current position), which is said to have possibly originated from the centre of the circle.

From the Stonepages link (http://www.stonepages.com/france/petitstbernard.html):
"A porphyry stone pillar, known locally as Columna Jovis (Jupiter's Column), could also have been part of the circle. This column now acts as the pedestal for a statue of San Bernardo, and stands near the stone ring. Ancient books say that in Roman times there was a big ruby called 'Jupiter's eye' or 'Escarboucle' on top of the pillar."

My GOD I hope I can get to it!!!

G x