A photo of the corner, with a yardstick for scale, and masking tape (or edit the photo) to show the limits of the area you can afford for the bench would help.
You need at least 2' depth from the front bench edge to the front of any test equipment directly on the bench or shelved within 2' above it. Mount the PC under the bench, with a powered USB hub at the back of the benchtop, a wireless mouse or a trackball and the keyboard in a pullout keyboard draw so you don't have to clear bench space to use it. Where you mount the monitor is a matter of personal preference - either wall mount at eye level at the back of the bench or on a swingout monitor arm. Get a multi-input monitor that can handle the PC, HDMI and composite video, so you can use it for anything that needs a screen as well as the PC.