I would suggest Royal Canin. I get this for Artica and it is good quality. One of the better dog foods on the market. There are a bunch of different type so you would need to see what suits your dogs best. You should be able to get it at a good pet food supplier. I buy it at out local pet supply store. You can get a 15kg of royal canin mini, royal canin medium or royal canin large breed for about €50 maybe a little more for the large breed.

here is the link in spanish.
http://www.royalcanin.es/default.cfm