In defense of the cat (if that is even warranted), when they pee somewhere other than the litter box, it can be a sign of UTI (urinary tract infection) or other sickness. At 13 years old, she's getting up there in age. Have the vet give her a good check up.

Also, as an alternative to declawing, you can use Soft Paws. Granted, you'd have to re-apply the nail tips regularly, but it's decidedly more humane.