This is probably a task better suited to a 2D image editing software package. I did this in about 10 minutes in Photoshop, but PSP or the GIMP would be able to do the same sort of thing.

I've inserted objects from Carrara into photographic backgrounds, but the thing I find most difficult is lining the shot up with the camera in Carrara. Try to get the focal length of the lens on your camera and duplicate that in Carrara (Carrara's cameras are roughly 35mm camera equivalent). It looks like your camera is about 5 feet above the floor, and not square on to the back wall, so you'd need to match that in Carrara as well.

It can be done, but Carrara might not be the best tool for the task.