Generally when a goal requires you to buy wallpaper, you can buy any wallpaper to complete the goal. I remember that goal set and I wasn't fond of that particular wallpaper so I bought a different one. It generally works for floor tiles as well (any floor tile will complete the goal). What I do is try to purchase one floor tile or wallpaper and then exit design mode and see if it counted towards the goal before buying more. On some of the newer timed goals, like the movie goals in bakery story and the Halloween goals, you have to buy the suggested floor tiles but can buy whatever wallpaper you choose. Just try buying something different and see if that works. Hope all goes well for you
. Let us know how it works out.