You shouldn't have to re-do anything at all on your router. The NAT that Parallels creates in the 10.x.x.x range is completely contained within your MacBook. All of the network traffic from all VM guests, along with your Mac OSX traffic, is piped through your single 192.168.1.10x address.
So it sounds like something else is going wrong here. Whatever you do, DON'T change your router.
Did you ever get your setup work with Host-Only Networking and Internet Connection Sharing? If so, it should work to edit your VM settings, change the adapter from Host-Only Networking to Shared Networking, and then restart the VM. Try going back to host-only networking+ICS first, get that working again.
Last edited: Oct 29, 2006