1) No, past years mugs are not eligible for refills
2) Yes, if you want to get free refills you would have to purchase the new mugs on your trip.
btw, WDW just came out with new mugs with different designs on them, here is the link (just in case you are interested in what they look like):
http://www.disunplugged.com/2009/02/11/new-walt-disney-world-resort-mugs
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