My Dog Has Enlarged Liver - What Can I Do?

My dog us around 12 years old, 20 lbs, Jack Russell/Shitzu mix.

In 2008 I was told my dog had a mass/tumor that effected her liver, kidney and pancreas. She almost passed away.  I changed her diet to raw, added milk thistle, Flor Essence, etc.  She survived, but the mass in her tummy continues to grow. Had high liver enzymes.

She really started slowing down over the past 2 months; not wanting to walk far in the morning.  Vet says she has arthritis as weel.  I have been giving her Glyco Flex, Wild Salmon Oil and Cold-Pressed Castor oil.  She is also on Pet Naturals Daily best (multi vitamins with digestive enzymes and antioxidants).

Went to vet 2 days ago and he took x-ray.  Told me her liver is enlarged; and that is why she has a large pouch.  Her tummy sags.  So I guess the mass is within the liver? Anyway, he re-tested her and her liver enzymes have dropped, but still high.  He put her on Denosyl.  But could offer nothing in the form of helping shrink the liver.

Online I read that an enlarged liver may be because of too much protein.  Is this true?  If so, feeding her organic raw food/meat has been hurting her.

Any advice on what I should do to help her liver decrease in size and lower her enzyme level?  Help with arthritis? I have to stop the liver from increasing further and causing her discomfort, along with her arthritis.

Thank you so much in advance.  My dog started having these problems around the same time that I started having fibroids.  We had moved to another state to help take care of my terminal sister.  The stress/pain of the situation took it's toll on both of us.