What to do about Rumba...

Mom and I are a little concerned about Rumba. She seems to be having some back problems... A couple of months ago we had to take her to the emergency clinic because she couldn't walk and was crying a lot. Of course she totally freaked out and the vet couldn't even examine her. Mom thinks she must have jumped down off the counter and hurt her back (she won't jump up on anything higher than a chair anymore). She's usually OK, but the other night it happened again. All of a sudden she was just crying and crying and she wouldn't let anyone touch her. It's very scary when that happens!!! I think we should take her to the vet, but I'm not sure how. When you try to take her she gets very upset and starts to hiss and snarl and snort. Hopefully, we'll come up with something, I don't like it when Rumba doesn't feel good...