The easiest solution to this, assuming you need to copy GPS info from one file to multiple files (not sure what you're actually trying to achieve), is to use the builtin SetAttr command to read the GPS information:
SetAttr META "copyfrom:11,{dlgopen}"
Select all the files which you would like to have GPS information copied into. In other words, your destination image files.
When you click the button containing the command above it will prompt you with a file request dialog from which you can select your source image file (this can be anywhere).
Once that's done the command will automatically populate the GPS information into your destination image files using the data in your source file.
Not perfect and may not be what you're trying to do. If you are actually wanting to copy GPS info from multiple source files to multiple destination files with identical names then you will need to write a script as @Jon has said.
If you don't know how to configure a toolbar button then How to use buttons and scripts from this forum will help - check the Raw Commands section of that post.