I would avoid anything with a fixed waistband at the moment and go for a jersey dress and jacket/cardi combo. This is really cheap and reusable for lots of situations. Wear a fitted vest underneath to pull your tummy in a bit (or do you have any control underwear?). Do you have a smart jacket you could wear over it? Something like this? Add a silk scarf in your best colour and this would go someway to hiding the bra issue too . Not THE most stylish outfit but if you dont think it'll be worn again then the cheaper the better. Check out supermarket ranges (TU often good), H&M or New Look. And best of luck for the interview .