The Pregnacare will have what you need....along with your regular diet. You can get Omega3 in some of the Pregnacare supplements so check which one you have. You can also get it by having some walnuts or flaxseed each day. Ground flaxseed works well in yogurts, on cereal, in a fruit smoothie, in baking, etc.
B12 is likely to be one of the biggest concerns, but many foods are fortified, even vegetarian varieties. It also becomes an issue if you are planning to breastfeed, so having good sources, and staying on the Pregnacare as well, will give you insurance of having what you and baby need.
Iron is often a problem for women in pregnancy so it may be even more of an issue for you....include iron rich foods, and if need be your gp maybe prescribe an iron supplement in addition to the Pregnacare if there is any question.