The moogle gives out a "set" of four cards that need to be distributed and then returned to the moogle for a prize. On the set's fourth return, you either receive the dream robe, or the dream robe + 1 if you already have the dream robe. Unless you track the cards yourself, the prize you get from the moogle seems pretty random since you won't know for certain how many times they have been returned to the moogle.

Something that worked for me was to find a person who fit the moogle's description, ask them to turn in the card, and then return it to me so that I know how many times it has landed in the moogle's hands. Do that three times, and then you're guaranteed that the fourth trade to the moogle would be a robe or robe + 1. The main drawback is that you hope the card's fourth turn seeks a job and level that you have. In order to receive the dream robe + 1, yes you have to be wearing the original dream robe.

Also, you may want to hold onto the fireworks if you are still looking for that dream hat + 1. There is a smilebringer in each nation, and by talking to him and handing out presents or fireworks to children, you may make enough children happy to receive a gift beneath your Mog House christmas tree (which you can by from some moogles in each nation)!

Edited, Wed Dec 21 11:40:20 2005

You might want to read the first announcement explaining the christmas event. There is a mention that we will be delivering christmas card. It's not really that clear, but it looks like fun