Accessing guest when host is on different network

I`m running a guest Ubuntu server 12 vm on a Windows 7 host pc.
The host computer ip is 10.0.0.1 and the guest ubuntu is configured as 192.168.21.129 (i dont want to change these ip addresses).

I`ve configured the network adapter as NAT with subnet ip of 192.168.21.0, gateway ip of 192.168.21.2, and forwarded the host`s 80 port to the vm`s 192.168.21.129:80

What do i need to do to make the vm`s webserver accessable from other computers on the lan? (Currently its accessable from the host but not from other lan computers)

Thanks