If you're using Outlook, there are a couple of things you can do: save the data to files as a backup, and sync to Google. Last time I tried the
Google Calendar Sync program, it was 2-way, but Calendar only, not Contacts.
You don't say what phone it is, but if it's a Windows Mobile phone that supports Exchange Server, you can sync it with Google (Calendar & Contacts) directly without going via the PC at all. The Contacts are added as Gmail contacts. Details are
here. This is what I do, now I don't run Windows any more: there have been a couple of hiccups, requiring me to delete and re-establish the connection, but no data loss.