Blog Background

I've seen everybody's cute Christmas-y (or Hanukkah) backgrounds and I have attempted to change mine without success. I can change the furthest background (like the wallpaper) but it leaves half of my old background (following the directions given on "Cutest Blog on the Block"). I may be stuck with it forever! If anyone has had a similar problem and figured out what to do please let me know! I'm getting a little tired of the polka-dots.