The ID for her dress has not been confirmed. This could be because it is either vintage or a custom job. It has a sloping neckline, 7 flat black buttons down the front with light marks in the center, either from a contrasting thread color or a design on the button, comes to almost a point at the base of the bodice, splits at the top of the buttons. It is made of a very shiny ice blue fabric.
This is the Vivienne Westwood Metallic Pannier Dress. It is by far the closest match I've ever seen, and all online mentions of it seem to be about the right age for the episode. The neckline is perfect, especially the wide sloping effect of the shoulders. It buttons up and has the split at the top. The metallic fabric is 83% linen and 17% nylon, and is extremely shiny. I've found a blue version of the dress, but it is in cotton, not the metallic fabric. I've not found evidence that there was a blue metallic version ever. Also, there are 7 buttons, but on the SA dress they are all on the bodice, while in the Pannier Dress there are two spaced below the waist. Also, while the metal rings inside the buttons would account for the white marks seen in the SA buttons, none of the dresses have contrasting buttons like the SA dress. But I find the resemblance a bit too close to write off as coincidence, and I'm currently of the opinion that the dress was neither vintage or a custom job, but some similar nock-off of the Vivienne Westwood design.
Probably vintage, her coat is a Russian or Soviet Navy dress coat. It has shoulder tabs, a white cotton lining, only one row of buttons, and breast pockets with buttoned flaps. Recommend: search eBay and Etsy for similar coats and alter one to match better if you want.
This was probably a vintage find or an expensive designer bag. It is barely seen, but is a white or silver beaded clutch with a silver chain. Again: search eBay and Etsy for similar alts.