When taking omega 3 I think of it more as a food rather then a suppliment, because it needs to be in balance with omega 6 and 9 fatty acids, the intake of these fats can vary day to day and vary greatly from person to person. Eventually you will find out what is the right amount to take for you based on general wellbeing.
Personally I would prefere to get my Omega-3 and vitamins from seperate sources, as I have no idea how much vitamin A and D and omega-3 I would be taking per tablespoon of codliver oil.
Vitamin A intake is usually supplimented at 2000-5000IU per day, and vitamin D is usually supplimented between 100-1000IU per day, Vitamin D can become toxic at as low as 4000IU per day, so you wouldnt wanna go too hard on codliver oil, although I imagine it would be hard to acomplish because if you were to consume too much omega-3 you would know about it. Personally symptoms of too much omega-3 for me have been brain fog and heavy breathing, wich quickly subsides with the intake of omega-3 competative foods such as chips.