Are you behind a router?   If so the ROUTER'S IP is the gateway, which is either:
192.168.0.1 or 192.168.1.1

DNS is Domain Name System, Internet system to translate names into IP addresses, why are you using that on a network?  You only need:

IP Adress (192.168.1.xxx or 192.168.0.xxx)
Subnet Mask (255.255.255.0)
Gateway (192.168.1.1 or 192.168.0.1)

You should be using DHCP (PS3 getting it all automatically).  If you are MANUALLY setting this up, then you need the DNS from your ISP, which you can get from your PC when it is on line, and connected to the internet:

First you must find DNS server information.  To do this, using your PC:
Go to network connections. Go to status > support > “Details”

you will see something like this:
DNS 1: 67.99.78.12
DNS 2: 67.99.78.13

Those are your ISP's DNS server addresses.    Why do you want to set this up all manually anyway? You can't use your own IP address anyway.  That will also be shown in the DETAILS as explained above, what IP address your PC has.

UNLESS, you are behind a router, for which this should be all done automatically anyway...