Yep, definitely take her into the vet. Again, I can't really tell from the picture what it looks like, sorry
But get her into an avian vet and see what they say. You can start by checking the yellow pages. If you don't see any listed there, you can check here:
http://www.aav.org/vet-lookup/If you still can't find one, then call up some regular vet offices and ask them if they know of any avian vets or a good regular vet who deals with birds.
As for prices, it varies. Just depends what that bump is.