From the sound of it, the OP has already figured out basic flying. He probably won't need an instructor in the traditional sense since he is able to take off, fly around, and land on his own. There is nothing wrong with his plan to add to his collection now so he can keep enjoying the hobby alone and then joining a club and expanding more later.

To cgenius80- What the club will do for you is give you a group of guys who will answer your questions when you ask. RCUniverse is obviously a resource for that too, but there is nothing better than having people there with you who can check over your planes and make suggestions, see your flying and show you how to improve, and involve you in conversations about all aspects of the hobby. But I'm glad to see you progressing by yourself. That Sport Cub is a nice flying plane, but you are right that it does get tossed around by the wind a lot. If you are flying it competently though, I wouldn't get an Apprentice. Go with a sport type plane and have yourself a great time.