Congratulations Panthyra on starting your treatment, that's really great. Within a week of starting, most people will feel better than they have for years.
After starting treatment, little monitoring is required. The most important test is the viral load test : 'HCV RNA PCR (Quantitative)'. It's recommended to have it at 4 weeks into treatment (the virus should be undetected by then), then again at 12 weeks, and finally at 24 weeks (If you are undetected at 24, you're cured).
Your body does not typically need supplements. A normal diet consisting of a variety of foods is sufficient. While most supplements will be harmless, and will not interact with your medications, they have not been studied, so it's recommend you do not take them during treatment. If you insist, take them at the opposite end of the day to the time you take your medication.