Hello there,
There is a letting agent just over the square called Morales ( I think) Some friends of mine , that live in Spain, rent their house via his agency. He has English speaking staff, I think if you are going to Spain in the near future you should pop in and have a word. Please bear in mind though, that there are lots of properties up for rent, I have got one myself in Phase 1 of the "Luz". I have been trying to let or sell it for 2 years, and apart from one clown who disappeared before he paid his first months rent, I have had no luck. Be careful who you entrust with your keys, as some unscrupulous agents will put anybody in your apartment (the stories I have heard ! )
Good Luck.