That depends on whether you want to link the calendars (so entering something on one will show up on the other), do it unidirectionally (only changes on one of them will show up in both of them) or bidirectionally (you can make the change on the PC or the phone and it will show up on both) or just copy what's on the phone calendar now to the C as a one-time thing.
Google
link google calendar to Android and you'll see many links to link the calendars in different ways. (If you want to "download" it so it shows on your Windows calendar, try
link google calendar to Windows.) With enough work, you can link the phone, the PC's calendar and
Google Calendar (and others - I have Cozi linked to mine also). But it is work (maybe only half an hour, but it seemed like work to me - it would be so much easier if all calendars could just take and give ICS links.)