flyinlynn has given a good response, Karigra. Basically, you need to find a hepatologist in a liver transplant center, or else a hepatologist who treats HCC.
Your mother can have two samples taken in the same biopsy: a sample of the tumor and a sample of the non-tumor liver tissue to deterrmine the degree off HCV damage. These should be done soon.
If you were in the counry I live in (Argentina), I would recommend you send your mother to the head of liver oncology at the German Hospital. Since you don't live here, you need to find someone in a similar capacity.
Your mother's life can perhaps be saved, but that depemds on her receiving the proper attention at the proper time. If the tumor is not malignant or not too advanced, it can be removed. Her HCV can be cured with the new drugs. But all this must be properly diagnosed and coordinated by the right people. It's up to you to find them.
Good luck.
As it turns out, the liver tumor was the type of cell found in metastatic cancer which isn't unusual, generally speaking, but unusual because she's had Hep C for 15+ years. There is no cirrhosis. Next step is a PET scan to see where the cancer is originating or has spread.
She should see a hepatologist (liver specialist) associated with a liver transplant center. They will be able to answer all your questions. A hepatologist associated with a liver transplant center are best equipped to diagnose and follow a patient like your mom. Her current doctor will provide a referral.
There can be liver masses that are harmless. I had 5 liver biopsies over the years prior to my cirrhosis diagnosis in Jan 2008 performed by a gastroenterologist. Even if it is a liver tumor it can be surgically removed under certain circumstances and leave the remaining liver intact.
If she does have HCC the type of hepatitis c is a secondary concern. To determine the genotype of hep c she will need a genotype blood test to determine her genotype.
Treatment for hep c had major changes a couple of years ago. The new medicines can cure the majority of people not previously treated. Treatment could be as simple as 1 pill a day for as few as 8 weeks. But which treatment and duration is determined by a number of factors.
But first it needs to be determined what is going in it's the masses then go forward from there.
There is a lot of good general information about cirrhosis and liver cancer. Try the Mayo Clinic web site also the VA has some good information in layman terms
Best of luck to you both.