I would suggest that your .m is a function that gives a specific output. So, from the previous post (depending on how many outputs your .m file has), you can do this:
Now, if you want to set the value into the edit box, use the set() command
set(handles.editbox1, 'String', num2str(output1))
handles.editbox1 is the tag of the box that you want to edit and output1 is the value that you want to display.