IP Networking

Hi guyz,

got a little bit of a situation here. we are sharing an ADSL link with
another organization. so there are 2 networks.
network 1:
has the adsl router and the whole n/w is on subnet 192.168.0.*
the adsl router has its ip as 192.168.0.1

network 2(now us):
we have set up a linux box running Centos 4.3 to act as a firewall,
proxy and dhcp + file server. our network is on subnet 192.168.1.*
the linux box has two NICS:
eth0:192.168.1.1
eth1:192.168.0.6 (varies since it takes ip dynamically from the adsl
router on n/w 1)
on our network we have a domain running on 2003 server....n our dns is
also on the 2003 machine.

scenario:
from the linux box.....i can be able to surf the net, but all the
other client machines on our network (192.168.1.*) cannot access the
net. i cannot ping the adsl router or any 192.168.0* address from the
client machines, but i can do all that on the linux box.


now am suspecting i need a NAT....or a router to join the 2 networks.
however, i would like to utilize the linux box for the job (as a
NAT/ROUTER).

Can anyone help me get through this situation....i really need to sort
this out!
or if anyone can help me get the client machines access the other
n/w.....i would be grateful...coz then i can proceed n share the link.