John,
You have a USB printer, not a network printer. You are trying to share that printer over the network. The printer doesn't/can't have its own IP address. It is hosted at the IP address of the Windows computer.
You will not be able to use the Epson-provided driver to print to the Windows-shared printer. Epson provides USB-only drivers for its USB-only printers. You will need to use a Gutenprint driver. Apple has included Gutenprint drivers in OS X for this very reason.

http://docs.info.apple.com/article.h...5/en/8671.html
http://macs.about.com/od/macwindows/...nprinter_4.htm
http://support.apple.com/kb/ht3049

For Gutenprint updates:
http://gimp-print.sourceforge.net/MacOSX.php