R. Trevor Davies, THE GOLDEN CENTURY OF SPAIN, 1501-1621. I'd start here. There was a Harper paperback reprint you should be able to find. He's a fan, especially of Phillip II, and writes well.
J.H. Elliott, IMPERIAL SPAIN, 1469-1716. If you can read only one book, this is it. Thorough and more up to date than Davies, more objective and a little less dramatic for it.
R.B. Merriman, THE RISE OF THE SPANISH EMPIRE IN THE OLD WORLD AND THE NEW (4 volumes). The classic.
L. Ranke, THE OTTOMAN AND THE SPANISH EMPIRES IN THE 16TH AND 17TH CENTURIES. Written in 1843, scarcely 50 years after the end of the GC, it's still full of insights if you can find a translation.
E.J. Hamilton, AMERICAN TREASURE AND THE PRICE REVOLUTION IN SPAIN, 1501-1650. Hamilton took Deep Throat's advice and 'followed the money' way back in 1934. His work has come under attack in modern times, but he first broke the ground that Braudel, in works others have noted, plowed in remarkable detail.
Even Braudel's work seems superficial when compared to SEVILLE ET L'ATLANTIQUE. It's a massive--8 volume--study of the economies of Spain and its American empire in the period 1500-1650, by H.& P. Chaunu So far as I know it hasn't been translated, though.
If you're interested in a modest (180 pp.) survey of the wider European economy of the period, there's Harry Miskimin's THE ECONOMY OF LATER RENAISSANCE EUROPE, 1460-1600.