please help me with my comodo firewall and ICS

Hi im a new member to this forum so please be friendly with me (:LGH)
Anyway the computer i am currently on has comodo firewall pro on it.

I recently bought a new computer for another room and have connected it to this computer via ICS (internet connection sharing).
however i have run into a problem.

This computer that i am currently on runs absolutely fine with CPF running, however the other computer will not go on the internet it just times out.
When I disable the firewall both of the computers work fine.

I spoke with a friend who tells me i have to allow the other computer in the network settings on my firewall by allowing a certain IP address etc.

However i really dont have a clue how to find this IP address and allow it etc
so could someone please give me a step by step instruction guide on how to get this firewall to allow my other computer and how to find the other computers IP address etc to allow it to work.


ps. both computers are running windows xp home sp2