It seems difficult to get good maps for walking (1:50,000 or better) of regions in Andalucia. I suspect that this is also true of lots of other areas in Spain. I tried Amazon and Stanfords without much success. Stanfords do list 1:50,000 maps of most of Spain but they hardly have any of them in stock; they have to back-order them. I did try and order some maps for walking from Stanfords 3 weeks before leaving the UK but I didn't get them in time.
So, I tried to get some maps when I was in Spain, trying the local tourist information offices; I even went to one of the main bookshops in Malaga - Libreria Luces. Apart from 1:300,000 road maps and a few walking maps to regions we were not visting, they had little to offer.
However, on the last day of our holiday we did meet some Spanish people that pointed us to a map shop in Malaga:
http://www.mapasycia.es/#
which seems to stock lots of good maps. Their other tip they gave us was to visit the local town hall of a region which often has much better information on walks, paths and local maps than the tourist information.
So if buying detailed maps of Spain, order them well before you go (a couple of months) and once you are there you can try the suggestions above.
Post edited at 13:32