There are tons of things you can do.
They make a wall paper that is textured. It is embossed with all sorts of patterns. From real antique to more modern designs. This paper is a bit thicker then normal wall paper and can help bridge very small gaps and hide some minor issues with the wall. It comes in basic white and allows you to paint it any color you wish. There is also some that have a color in the pattern already.
If the wall is in real bad shape, you may want to touch up any larger defects with spackle to assure a smooth finish with the new paper. Ideally you should remove what ever paper it is that you have or in the future it will be a real pain to take two layers of paper off of the wall.
Here is a link to some of the real fancy types out there. http://www.grahambrown.com/us/wallpaper-brands/Superfresco*
See if you can simply skim coat over the wallpaper?????