Hi BuzzyBee, and welcome to Hamster Central!
I hope that she's doing ok after her vet check, and that whatever is going on down there heals on its own.
I'm glad you and your daughter are looking to take care of Anastasia and are doing your best to try and make her a nice and large enough home!
I have only had a dwarf hamster, so I can't help you with numbers for syrian cages, but I think they need to be pretty huge (the forum-recommended cages for dwarfs are pretty big, so imagine one for a larger hamster), and if you have a larger syrian, an extra-extra-large cage is in order.
Most pet stores do not have cages large and with enough room for deep bedding for hamsters... so it will probably be much larger than anything you've seen there labelled for hamsters.
Some people buy large aquarium tanks, or, as you are doing, make their own cages. Lots of people like taking Ikea furniture (Detolf?) and turning it into a hamster home as well.
You can take a photo of your current cage and ask for suggestions on the Housing subforum.
I hope you, your daughter, and Anastasia create many happy memories together!