Give some thought to carrying snack foods with you such as cheese, bread, fresh fruit and water. Other recognizable foods are available in groceries everywhere. This way no matter where you are, when the hungry hit, you are prepared with something to tide them over. From personal experience I know that a well-fed child is a content child. So be prepared.
Pharmacies offer other supplies such as bottles and food supplements.
Toys and clothing can easily be found at shopping centers. Vasco da Gama, the ultra modern mall at the Expo Center in Lisbon offers everything you can imagine. It is east to reach by subway and it is in a beautiful location along the shore of the Rio Tejo. What's more, all of the children's stores are located on the lowest level next to one another so you will not spend all day wondering about looking for what you need. Fine restaurants and attractions for the entire family are just a short stroll away as well.