I have Windows 7 64-Bit and have just gone through the Add printer wizard using Windows Update and I see 3 entries for your printer:
- Epson Stylus Colour 1520 ESC/P 2
- Epson Stylus Colour 1520H(KSSM+)
- Epson Stylus Colour 1520K ESC/PK .
Did you click on Windows Update in the wizard and wait for the list to update?
I do not know which of the above you should use even if you do manage to get them listed. It may be worth emailing Epson directly for advice.