You may use one of the common filesharing providers to share your files (e.g. Google Drive or the like).
However, I think your screenshot does clarify the matter.
Unfortunately, there is no straightforward way to do what you are looking for. In case you are just talking about a couple of filled paths, I would recommend to simply divide them at the (virtual) end "points" of the filled path. That is, take the Direct Selection tool, select both path segments that are located where an end point of a stroked path would be and delete those segments. You will get two separate open paths to which you can apply a stroke attribute. You may then additionally delete one of them or you can do a blend between them to match the exact centre line (see Blend tool).
Of course, if you are dealing with a lot of filled paths that are going to be converted to stroked paths, you may have a look at Live Trace. In that case you would first have to convert the filled paths to raster images and then trace them with the option to create strokes turned on. This way may or may not work as expected and it usually requires a good portion of experiments to get good results.