I don't want to give her away, but she just won't stop urinating!

Hi there,

I have a one and half year old tabby cat, that I adopted from the
humane society when she was 8 weeks old. I also have a 3 year old cat
that doesn't generally seem to be to bothered by the little one. I
changed residences about 7 months ago and in the past 4 months have
been finding my cat urinating on our leather sofas and in corners of
the house on the carpet. The vet has completed a urinalysis test on her
and claim that her issue is not medical but behavioural. I can't seem
to get the smell out of the leather sofas and I have tried many things
such as the odor out spray from Pet Smart, dishwashing liquid,
Fantastic, baking soda alone & baking soda+peroxide. I thought if I got
rid of the smell she would stop. The smell is still there and she still
won't stop peeing. I have tried keeping the sofas covered with boxes,
but as soon as I remove the boxes for guests, she pees. When the sofas
are covered she started using corners of the house where there is
carpet. I have also tried using Feliway spray and the Feliway diffuser
in combination which originally seemed to work, but does not seem to be
working anymore. I have covered all of the corners where she generally
pees, but then she finds another corner to pee on. I have also tried to
deter her using repellent from Pet Smart, which did not work at all. We
thought if we put catnip spray on the leather sofa that would keep her
from peeing, that also has not worked. I have changed the litter
material to pine needles, which she seems to like. I also have three
litter boxes set up in the basement. After trying all these different
things to try to stop this bad habit, with no success, I feel defeated.
I am so frustrated that I can't seem to address this problem, that i am
really close to giving her away. I really don't think there is anything
more I can do, because I know eventually she will go back to peeing on
the sofas. Currently I have paper towels on the sofa and inside the
sofa to try to catch the urine, but the sofas still smell quite bad. I
think i may have to replace those too. Please if anyone can help, I
would hate to give her up!

Thanks,

G.