post office address on camino

I'm not sure where you are but I had some stuff posted to the Santiago Post Office this year, was sent on a 3-5 day post from the UK and when enquiring in Spain I was told it would take at least 15 days to arrive!! (I gave it about 12 then had to give up) If you decide you are absolutely desperate for this map I would have it sent it by next-day courier to somewhere you are staying although that might be expensive...
I'm tempted to say something spirit of the camino-ish like don't worry about it - you'll find your way without a map or if you need it a map will find you...! (Sorry!)

Just follow the yellow arrows and other pilgrims... Many pilgrims have done just that before, and many more will do it in the future.

Smile, relax and have a great Camino.
David, Victoria, Canada.

To address mail to yourself put your surname first, in capitals. When you go to collect mail, take your passport as ID; and to be sure, ask them to check under your first name as well as your surname. Here's a list of places along the Camino Francés, with postal codes, 2 or three days apart:
Lista de Correos
31080 Pamplona (Navarra)
31100 Puenta la Reina (Navarra)
26080 Logroño (Navarra)
09080 Burgos
24080 León
24700 Astorga (León)
24400 Ponferrada (León)
27600 Sarria (Lugo)
15780 Santiago de Compostela (A Coruña)

So example:
SMITH, John (Pilgrim)
Lisa de Correos
31080
Pamplona
Navarra
Spain