I personally have added an extra "meal" to my tracker page, called Supplements, as I want them listed separately.
Look at your bottles of vitamins, make personal entries that match your amounts contained in them and then you can easily track on the nutrition tracker.
To add a new section:
Click Track My Food
Scroll to the bottom, there a load of buttons, the bottom one is Add/Edit Extra Meal
Click that, and add a section called whatever you want
Track your vitamins!