Hello Spr,
You can get your media by navigating to below location.
service market place-> software downloads-> Installation & upgrades-> A-Z Index-> click on letter N-> select sap netweaver-> select your systems NW version and corresponding EHP->Click on installation & upgrades-> select your os-> select your db
when you scroll down you will be able to see files to be downloaded. In check box select NW 7.XX Language 1/N N- number of parts for that file add all parts and add to download basket.
after u download and extract u will have entire language pack for your system recommendation. select ES- Spanish language from that folder.
and for language installation you can follow this guide http://scn.sap.com/community/netweaver-administrator/blog/2012/12/10/installation-of-languages-on-sap-systems
Hope this helps.
regards,
Bala