Make Simple PCB and export Gerber file
Geda PCB will also let you draw your layout directly, sans existing schematic (this is in fact an essential part of Geda philosophy, being a toolbox rather than mega-does-everything-in-one-program), although it kinda wants you say what parts those things you place are going to be. Looking at the datasheet of your volt/ammeter it seems it uses a single row of pins, so you can probably fake that with quite a number of other parts if you're impatient and don't want to add/define a custom part. I can't find the pin spacing in the datasheet though, so you're on your own for finding substitutes.