Help - any ideas of a winter dress for 80th do!

[Squigglywiggly]

In a couple of weeks I am going to a big family birthday bash (husbands side). Looking for a winter dress that is not too formal. ? A woollen one. Couldn't find any in shops and don't have much time left or patience! Any ideas? I am short, size 10/12 (baby belly still left) and not too buxom if this helps!