How can I have a new key made?

If you were the first owner then the dealership would still have the key code on file for your vehicle. If you've always had it serviced at the same gm dealership, again they should have it or could get it from the original dealership it was sold through. If you can get this done then have them make you 2/3 sets of keys as they charge a flat shop labor fee to do this. The keys are cheap, so they make their money from the cutting and programming of them, so the cost to make 2 or 3 is about $10-20 more overall than the cost to make just 1 key. If the cost is really high then have them make just 1 key and then check other online local sources that can copy or make them for a fraction of what the dealerships charge. A Honda dealership charges about $150 to make a new key from another working one, or from their original sales records. Most locksmiths can cut and copy them for you for about $50-60 each, including any programming. Even many walmarts can cut an immobiler key purchased from eBay for as low as $10, then have the locksmith copy or program it for you for about $25-40 each. Its always better to have spares then nothing at all.