heres a really good tip i read in a cat magazine once, one of the biggest mistakes cat owner make is bringing the cat carrier out when its time for the vets. This associates those stressful visits with the cat carrier. "oh no the humans got the carrier out..run!!"
In the future place the carrier in a familiar place with a nice pillow and if you dont like the look of it on the floor cover it with a pretty blanket.
I leave my cat carrier on the landing and some times my cats go in it to sleep and some times they play in it.
Let your cats become familiar with their carrier that way taking them to the vets in a familiar bed will be a lot less traumatic and I find my cats will happily walk into the carrier when I pick it up and place them near it.
hope thats helpful and good luck !
Also if you leave the carrier out and she doesnt go anywhere near it make it interesting by placing tasty nibbles inside and when she realises she doesnt get locked up as soon as she goes in she might start to settle in there over time