Field Contains The Full Pathname Of The Image

I work for emergency services, and one of my colleagues has a GPS camera that snaps digital pictures and collects the coordinates where the image was shot. These coordinates are recorded in a database file readable in Excel. The emergency mapping software can load these points along with the images, but in order for the hotlinks to work (and thus be able to click on a point and load the image), I need a field in the database file that shows the full path name of the respective JPG image. As it is, the database file has a field (named ORIGINAL) that records just the filename of the image.

I need a field that contains the full pathname of the image. This is easily done in Excel, but I need an external script that will run this outside of Excel because I need to streamline the process. If dispatchers need to go into Excel and edit columns to make the data show up, they're not likely to bother.

I have a blank (not populated) column in the dbf (named INTERNAL) that I can use for the full pathname. What I want to do is begin with the text "C:/" and insert the text in the ORIGINAL column immediately following this. Is there a script, such as in a batch file, that will run this outside of Excel?