You can retro-fit your desk to achieve a similar set-up as a computer desk by using an adjustable keyboard tray and monitor stand.
Featured are two different keyboard trays; each comes with a 17- or 23-inch track. One has the mouse on the same surface as the keyboard tray, and the other has a separate adjustable surface for the mouse. The 23-inch track is more suitable for placing the keyboard tray in the corner, because a larger track will be needed. Both keyboard trays have soft, firm, and slim wrist rests that are very comfortable.
When installing a keyboard tray, I have found it more comfortable to offset it to one side by an inch or so, instead of centering it. If you are right-handed, offset it to the left; if you are left-handed, offset it to the right.
If you need a wrist rest for your keyboard or mouse, check out some of these at my miscellaneous office products page.