Hey CL215,
If you already have it in spanish, just look for "translation agency" around your location, I'm at Mallorca and I used Alphatrad, though they provide their services all around Spain, it cost me 72€ because I needed it in 72h, if not it was only 60€ which I think is reasonable. But any other official agency will serve the same purpose, what you're looking for is a "traducción jurada" I believe for it to be "official".