You should stick with your 18-55mm until you find yourself good enough to upgrade. actually 18-55mm is a good enough lens for most purposes. And since you do not yet know what you really want bcos from the description you have given, it practically cover too wide an area and it only show that you are not sure of your own needs and wants yet.
they are basically the same focal length.. my advice is not to buy anything yet until you know what type of photography you are more into.. and even then, you may or may not need to upgrade, cus the kit lens is a very versatile lens, that's why it's bundled as kit lens, for versatility, so that those who just got into photography can find it easier to use..
That's a sound decision. When you learn more about what the 18-55 can do and cannot do, then you will know what you should get next ... if there is a need to. Along the way, you will learn your style of photography and what you like to shoot. That will aid your next buying decision. Don't buy just for the urge of buying or whatever people tell you to buy. Enjoy shooting!