I know you could get the gold package from a cadillac dealer, but I guess it really depends on the year, if they'd still be able to order you one. I got one priced for myself for a '93 sixty special, and it was about $500. Ebay is also worth a try. Hope that helped somewhat for the gold package portion of your question.
You don't have to replace your emblems with new gold ones. Contact the dealer's aftermarket person. They should be able to hook you up with a company that does gold plating. You can have your existing emblems plated, and they don't even have to come off of the car. You could also check with some of the detail shops and maybe some tint shops in your area.