I don't think yr kitty can wait any longer for a Vet visit, or at least while there with the male cat ask yr Vet to presciribe an antibiotic for the queen, sounds very much like an upper respiratory infection (UTI) if left unchecked it could become fatal, it can also spread to the little kittens
This was likely brought on by the stress of birthing and the surgery combined. Tell me why ur waiting until later to give her the better canned food diet? She needs the better quality HIGH protien diet, esp now while trying to nurse and feeling unwell
She also needs an amino acid called Lysine to strengthen her immune system and help her overcome this URI
A real good one that I use for my cats is in powder form the brand name is Carlson Labs, I can give you ordering info if you can't get locally at a nearby Health/ vitamin store(human) or you can also get thru your Vet clinic, most clinics carry this...
here is a link to the one I order, its very safe and effective for cats. if you order this one there is a green scoop inside, a full scoop will be 1200mgs. I would give kitty a half scoop mixed with a bit of water by a dropper....until all symptoms have stopped...even while on an antibiotic