the better question is why do you feel like you need an upgrade? are you not getting the performance you want? do you wish to move into 1440p or 4k gaming?
maybe an upgrade to a nice shiny case can give you that "new" feeling you are missing at this point! if you really want to spend some cash how about a nice new monitor that may be more than your card can do now but sets you yp for the next gpu upgrade later on.