This tells me to:
Step 2: Click the "Configure IPV4" drop down menu next and choose "Manually."
Step 3: Type in your new IP address in the box under the TCP/IP menu. Simply delete the number that is in there and enter your new one.
What numbers do i put in for step 3 though? When I see what numbers are there right now it shows "0.0.0.0" and it wants me to put in numbers for the zeros. I'm not sure what numbers to use though. Surely it is not just random numbers?
Oh and I am using the exact same Macbook as you. The aluminum unibody one.