No they do not I had some from last year and they DID NOT melt they stayed fresh until I used them ;p
You can't, those are for a random event.
The store
No store in Runescape does such.
Most of the towns in runescape have a general store.
Order it off RuneScape's web store.
There isn't an Archery Store in Lumbridge.
Gnome General Store.
You can get one at the General Store.
Get the mime random event, and choose the 'costume point', then travel to varrock and go to the clothing store and use your point and pick which piece of the mime costume you want
A common store in the United states in general to get Christmas cards is Hallmark. They sell great cards for a low cost for any event that one needs.
The world's largest Christmas Store is Bronner's CHRISTmas Wonderland in Frankenmuth, Michigan
at any general store