If you want more of a “popup” approach, this could be of help:
What it basicly does is updating the widget along the way. It will remove the previous widget, if you walk over the next currency item, but add a new one, so the widget is kind of “refreshed”.
It will also reset the delay timer every time you run over a currency item and is run independantly, so it will be removed if you go over 3 seconds.