Lovely dress. I'd go for silver shoes - either with silver clutch, or dusty pink, as suggested already. But wouldn't go for pink shoes and bag - a bit too 'matchy' and also not very autumnal.
Afraid I have no great ideas on cardigan/ jacket. Would think a cropped jacket might be more 'weddingy' - perhaps in a pearly grey/ silvery colour, to pick up the grey in the dress? L K Bennett can be a good place for that sort of thing.
If you fancy a cardigan, you might want to look at the cropped cardis in wool and in cashmere in the new Boden autumn range - they usually get good reviews and there sems to be a good choice of colurs.