How can I fix my job mistake?

Once again my fear, impatience, & desperate-for-a-good-job attitude has caused me to once again mess up in the career world. I finally got a job at Walmart as a people greeter...WHAT WAS I THINKING!? I want to work as a sales floor ociate, but I have to wait until a position becomes available. I don't want to quit, but I don't know how long I can wait. It's BORING as a greeter.