Cow's milk or soy milk is fine to give after 1 year. Toddler formula is a marketing ploy to make parents believe their toddlers need it. They dont't, especially if they have a balanced diet. Formula won't make them any smarter than cow's milk
Relax. It is also not that important to drink lots of milk after 1 year. Try offering cheese or yoghurt or other foods that are high in calcium. Green leafy veggies are good too.