Any Fritzing part in fzpz format contains the necessary files to modify it (an fpz file and 4 svg files all zipped typically). However I'm unclear what the pin spacing issue is. From the photo the pins appear to be standard .1 in (2.54mm) spaced header strips. That matches the pin spacing in the part from github. Does the board you have use something like 2mm headers? Or is the issue spacing between the sets of pins (the github part is .9 inches wide which is pretty standard for these types of thing is yours more or less than this spacing)? Parts modification is fairly complex although useful to learn if you want to use Fritzing. If this is all you want to do it may be easiest for me to make the changes for you. To do that I need the dimensions of the changes you need made (typically I use vernier calipers to measure the dimensions on the board and get close to the position and size of mounting holes). There are a couple of tutorials on making parts using Inkscape (an open source svg editor) available here:
if you want to learn how. Ask questions here and one or another of us will probably answer as we need more people making parts.
Peter