I'm not aware of any way to transfer GM card points.

But if you and/or your wife travel abroad with any frequency, the card will be very useful. It's issued by Household Bank (HSBC) which is one of the few banks that still charges only a 1% foreign exchange fee. Most of the major card issuers assess a 3% fee for all purchases made in another currency, so you can save a considerable amount by using the GM card when you go out of the country.