Online versions of the Greek text are available at:

• Ἑρμου του Τρισμεγιστου - ΠΟΙΜΑΝΔΡΗΣ on w66.eu,
• «ΕΡΜΗΣ Ο ΤΡΙΣΜΕΓΙΣΤΟΣ»: 240. – Ποιμάνδρης on Greek-Language.org,
• HERMÈS TRISMÉGISTE - Greek and French side by side (the Greek text is probably incomplete).

I have not been able to find text versions of the Latin text, i.e. Ficino's Latin translation. All I come up with are scanned version, e.g.

• De potestate et sapientia Dei (Tr: Marsilius Ficinus) on Archive.org,
• Mercurii Trismegisti Liber de potestate et sapientia Dei per Marsilium Ficinum traductus ..., on Archive.org,
• the list in the BnF database.

Online versions of the Greek text are available at:

• Ἑρμου του Τρισμεγιστου - ΠΟΙΜΑΝΔΡΗΣ on w66.eu,
• «ΕΡΜΗΣ Ο ΤΡΙΣΜΕΓΙΣΤΟΣ»: 240. – Ποιμάνδρης on Greek-Language.org,
• HERMÈS TRISMÉGISTE - Greek and French side by side.

It is not clear whether these Greek texts incomplete, however; they are suspiciously short.

A Latin version appears to be available on the blog Pymander Aquarian: The Pymander in Latin. 

Ficino's Latin translation is easier to find as a scanned version than as text, e.g.

• De potestate et sapientia Dei (Tr: Marsilius Ficinus) on Archive.org,
• Mercurii Trismegisti Liber de potestate et sapientia Dei per Marsilium Ficinum traductus ..., on Archive.org,
• the list in the BnF database.