Setting the ip address for the printer can be done using the Epson NetConfig utility. First note the first three sets of numbers in the NetConfig utility that your printer currently has. For example it might be 192.168.1.53. Highlight the printer you wish to configure and click "Configuration". Then select "Basic" under "TCP/IP". Click the checkbox for "Manual". You can then enter the desired IP address (but first see below). The subnet mask will be 255.255.255.0 and unless you have made changes to your router the "Default Gateway" will be the IP address ending in 1. That is, if your printer was originally 192.168.1.53 your Gateway will be 192.168.1.1.
However, before this can be done, your router must be changed to allow some space for fixed IP addresses. By default, the DHCP service is configured to use all addresses from 1 to 255. Putting a fixed IP in the DHCP range can cause problems. Not sure how familiar you are with your router settings. If you wish you can email or PM me your Make and Model number I can guide you through the steps. If you have some familiarity with your router then these settings should be readily accesible as DHCP setting are usually fairly prominent. There will be a setting for DHCP Starting IP address and a Stop IP address. By default, they will span the entire range from 2 - 254 (1 being reserved for the router, and 255 also reserved). You just need to change one to make room for fixed IP addresses. For example, change the Stop address to 240. The the printer IP addresses can be asigned to anything from 241-254.
Hope this is not too overwhelming. Feel free to ask for clarifications.