I wrote my orgional message after skipping a few pages...so missed the fact you are keeping the buns.
Im really glad you're getting it sorted, and not taking it back to that breeder. You may want to get insurance for your bun, it MAY work out cheaper, although if this is chronic they wont cover this illness, but any future ones. Im debating it for mine now...Either that or putting money aside every month for vet bills.
I am glad you're using this forum. Just one thing to remember...some of us are hot headed when we read posts that sound like the animal is suffering, so may say things that sound harsh, but we're just trying to look out for the bun.
Btw your cage sounds a decent size for two minis, although the bigger the better, if you have time dont forget to let them run around the garden/house if you can!
Good luck with the bun, and hope she gets better soon!