How would your computer send an SMS to your wife? You didn't mention anything about how your computer will connect to the internet.
One way you can proceed, if you use your phone as a modem for your carPC, is by running an SMTP server on your carPC. Have your own GPS application polling every couple of minutes for coordinates and sending a properly formatted e-mail via the SMTP server. The e-mail can contain a simple maps.google.com link that includes the coordinates for querying.