Routing: Proxying through VMWare Guest

Running Ubuntu Breezy Badger as host and Guesting Windows 2000 on
VMPlayer.

Using Starband two-way satellite with a Gilat 360 MODEM for Internet
connection. Starband setup requires me to run software on a Windows
installation to work with the MODEM.

I want to run the Starband software on the Win2K VM hosted on Linux. I
need some help determining how to send all (HTTP) ingress/egress packets
through the VM. If there's a way to get the VM to use the same IP address
as the host, that would be ideal.

Please forgive the ASCII graphics, but here's what I need to do:

Internet <--> MODEM <--> NIC on Ubuntu Host
^
|
v
Win2K VM with Starband Software
^
|
v
Applications running on Ubuntu Host

In the end, I would prefer to go out to the LAN from the Ubuntu Host
(after pre-processing through the VM) over a separate physical NIC, thus
turning the Ubuntu Host into a kind of server/firewall. The prickly bit is
the introduction of the VM Win2K.

I sunk >$500 into the system and am paying way too much each month. Newer
MODEM does not require software but is another $500 and more each month.
Satellite is the only choice where I live.

I don't want to just run a Win2K box in the middle because I like the
steady-on robustness of the Linux box, (even emulating the Win2K box in
it, it's better than trying to run another box in this instance).

TIA