If Amadores is like the rest of Spain you won't have to bother to take anything with you. The Brits are well catered for regarding food. (except the bacon is not up to much in some places)
I have just googled Amadores and they have a Lidl supermarket - depending where it is to where you are staying - but you will have no probs buying British foods there and there will be other big Spanish supermarkets who now sell loads of english stuff.
Cereals and milk, yoghurt and fruit breakfasts. We buy nice bread for lunch and have cheese, cold meats and salads - soup and bread - anything easy. Depends what your family like to eat.
Cooked chickens are lovely in Spain and loads of places sell them, some do the extras like potatoes and salads to go with them.
There are also the usual Mc places and pizzas and fast food - all depends what you like.
There are also shops similar to pound shops where you can buy plastic boxes of all kinds so just bring one to start you off the micro then you can buy cheap one and throw them away.

Just read on another forum that the Mirador apartments has well equipped kitchens so you should be ok.