If it's wireless, it should get an IP via DHCP from the router I think. Your router may have an "attached devices" list in the admin control panel, my Netgear MR814 does. Maybe it will show up there so you can find out the IP.
Along those lines, I'm not sure how your print server works and all, but if it needs a static or reserved IP, you will need to setup the reserved ip in your router. You'll need the MAC address of the print server to do this, usually there is a sticker on the print server to tell you this. Then reserve the IP in the router, and when you restart the print server it *should* get the reserved IP.
I have an IOGear wired USB print server, and when I setup the new printer, I don't setup a TCP/IP printer port. Instead I have to select a "Network Print Port". Maybe yours is similar. Check the documentation.
You may also be having issues with neighboring wireless networks. Try using NetStumbler from your main computer to see if anyone else nearby is running a wlan that may be conflicting with your setup.