ok I can help with the Linux questions, but I don't know the correct syntax for the routing on win2000, that's why I post here and not windowsquestions.org.
Can the laptop 192.168.0.2 talk to the ip address 192.168.0.1 ?
Set the laptops default gateway as the ip address to 10.10.0.1.
Don't need NAT on the windows system as it's just routing to the Linux box with internal ip addresses, but you need to tell the windozes system to route all packets from 192.168.0.0/24 to its other interface on 10.10.0.0/24
Then on the Linux box you need to allow the path back to the windows box.
route add -net 192.168.0.0 netmask 255.255.255.0 gw name_of_the_10.10.0.3_system_in_the_hosts_file eth0
route add -net 192.168.0.0 netmask 255.255.255.0 gw win_gw eth0
Then you need to make sure all the systems have routing enabled, ie forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward
Then you need to set up a default route for all other traffic to use the other card connected to the router with the real ip address.
Then you need to enable Nat for all packets coming into the internal nic to Nat to external nic.