This is going to be a different approach to making a room.  We are going to build it from the floor up.  I have provided a template3 for you to download.  This is done in layers and if you want to use it for other rooms, you can just delete layers.  You'll understand when you see it!

I started with a new transparent image, 600x450 pixels.  I flood filled this layer with white and named it Background.  I added a new layer, named it Floor and pasted my floor on.  (you can use the deform tool to alter the proportions of the floor piece.)  Next I added another layer and called it Walls.  Using the draw tool with the options below, I created 3 separate wall sections and a baseboard.  Note that the baseboard is all in red.

Using the magic wand, I clicked on each wall section, created a new layer, named them and flood filled them.  First make sure the walls layer is active.  Use the magic wand to select the left wall.  Create a new layer and name it left wall.  Flood fill it.  Make the walls layer active again.  Use the wand on the right side, create a new layer and name it right wall.  Flood fill again.  Make the walls layer active again, use the wand on the center, create a new layer named center and flood fill it with a different color.  Finally, make the walls layer active again, create a new layer and name it baseboard.  Flood fill it.  Oh, forgot the corners.  Make the wall layer active one more time.  Use the wand to select one of the straight blue lines.  Hold down the shift key and use the wand on the other line.  Now create a new layer called corners.  Flood fill both of them.  Now you can delete the walls layer.  When you open the template, you will notice that these layers are already there, but they are not filled with any color, and the wall layer has not been deleted yet.

I'm using one of the images available in the flooring supplies for the wallpaper.  I rotated it so that is was vertical.  Making the left wall active, I use the Fill tool, Pattern fill.  Well, it ended up with a line in it.  I increased the size of the piece I had picked using the Bicubic Resample when resizing.  Now that worked fine, so I also flood filled the right wall with the pattern.  When I went to fill the center section, I didn't like how that looked at all.  What I did was to create a transparent image 600x400 pixels wide.  I pasted 3 layers of the pattern piece on there.  I mirrored the left and the right.  After lining them up I merged visible layers and cropped to just the pattern.  Then I went back to the Fill tool, Pattern fill.  This time it looked fine.

Next, the corners.  I make the corners layer active.  I click on the Eye Dropper and pick one of the darker colors in the wallpaper.  Then I flood filled the two corners with that color.  Finally I softened both of them and changed the Opacity until I liked how it looked.  Note here:  If you had not deleted your walls layer where you drew your sections, it would show through.

Ok......do I really need to show an image here for the floor layer?  I simply picked the black marble and using the Flood tool, Pattern, filled the floor with the black marble.  Then I made the baseboard layer active.  Use the wand to select the baseboard.  I Air Brushed the baseboard selection with white.  Then I went to Effects, Outer Bevel with these settings.

To fix the little jaggies on either side on the top of the baseboard, I once again used the Draw tool with these options.  You'll have to zoom in enough to mark the correct place to start.  The antialias will soften the jaggies just enough that it all blends in.