When it gets to where it asks you about IP Address it should give you the choice for "easy" or "custom". Choose custom and set the IP address somewhere within the range your router hands out (192.168.0.110 perhaps). You should also set the other info if possible (router Ip, subnet mask, dns servers). This is found on the Status tab of the router settings.
I did some more looking through the settings and it looks as if you can't set custom IP addresses within the router itself (a bit off from the usual). So, we will try putting the IP address set for the PS3 in its settings into the router's DMZ.
Once you have this in go into the router settings on the computer and click on the Advanced tab, then down to Firewall Settings. Check the box that says "enable DMZ" ad put the same IP addres you gave the PS3 in the blank. In the menu beside it you should be able to find the name the router is calling your PS3- select that. Now hit the Save Settings button.
If this works your PS3 should pass the connection test and you'll be online.