There honestly isn't a good weight gainer that I've seen on the market. If you can, you're better off returning it and buying some whey instead and then adding what you need to (oats, maltodextrin, milk, etc...) in order to bump up the calories.
As far as creatine goes, I really don't think you even need 10g's of creatine a day; 5g's would do just fine. Also, don't bother doing the "loading phase" of creatine as it's basically a trick to get you to use it all so you have to buy more faster. Like imraan47 said, hit up the "search" and you'll find a ton of threads on creatine. | 
