With a 6 speed hub your current rear dropout spacing is probably 124-128mm wide, which means it can be cold spread to 130mm for a 10 or 11 speed hub. If you are mechanically inclined you can do this at home with some threaded rod and nuts. Keep in mind you will have to realign the dropouts after spread, which you can also do with some threaded rod, although the dedicated dropout alignment tools made by Campy, Park, VAR etc... will do a better job.