I would wear a large, dramatic brooch. I have 2 Lea Stein cat brooches (bought from the seller linked) 1 in ivory and 1 in red so would wear one of them. Failing that every charity shop and vintage shop has over sized costume jewellery. Other jewellery - small earrings, any colour or material. Bracelet in silver or gold or jade if that's something you already own.
sheryls-artdeco.com/product-category/jewellery/lea-stein/
To get to and from the venue or venues and to wear in church if needed if cold I'd wear my smartest coat. For that dress I have a vintage Acquascutum, just below knee length cotton coat in navy with a dramatic red swirly pattern which would go well.
Shoes, pointy ballet flat, or kitten heel in patent or velvet in any of red, green, fuschia or multi depending on the colour of the brooch. Pretty Ballerina has loads and if they're over budget supermarkets tend to have interesting flats. Definitely not nude and definitely not a bolero.