This product is not sold nor supported in North America. Please visit the D-Link International web site to see if a driver is available:
And fyi, this product was made in 2 different versions so be sure you know which device you have before attempting to use any driver:
1. DWL-G520+ Revision Ax.
2. DWL-G520+ Revision Bx
This product is listed on the UK D-Link website.