An inexperienced chess player may be well served to learn an opening and stick with it until he or she learns the basic concepts of chess. Once you have mastered the basics, or once you seem to be at a sticking point in your rankings it is time to try different things. In order to have a well-rounded game it is important that you learn and experiment with a variety of tactics and strategies. Getting stuck in a rut will keep you at the same rating that you have been at. An old saying that I like says, "If you keep doing what you are doing, you will keep getting what you are getting." In short, you will not improve your chess game unless you learn new ideas to improve your game.
That opening that you have been using for a year now is a functional opening, but now it is time to learn other openings and to experiment with them to see if they work for you or not. If you are using the same end game strategies that you used in your first dozen chess games, then it is time to learn some new end game strategies. The more that you know about chess and the various concepts the better your game will be.
It is easy for all of us to get stuck into a rut because many of us think "If something works why change it?" The reason to change your methods is because they may not be the best methods or techniques. The more you learn about chess and the options available, the more versatile you can be during your games. Knowledge is power and the game of chess has mountains of knowledge available for us to learn.