Internet share to DHCP Client

I have internet lease line in our company and
we existing server using win 2003. This server
connected to firewall and this firewall connect
to the router.

I am building another server for my testing
purposes. I have 1 windows 2003 server machine
that have 2 NICs. In this machine I have DC,
DNS, DHCP and Active Directory. I want all DHCP
client have internet connection.

In 1st NIC I assigned (For internal network)
IP: 192.168.10.8
Subnet: 255.255.255.0
Default: don't know?
Pri. DNS: 127.0.0.1

In 1st NIC I assigned ISP IP.

Please help me with this matter as I am new to
this setup.

Thank you very much in advance.