Quick question -- if you've already got a Windows computer, then why would you want to set up an emulation of Windows on Linux on another computer?
Anyway, to answer your question:
I think you should briefly switch your internet connection to the Ubuntu computer, install Wine via synaptic or apt-get or whatever package/program installer that Ubuntu uses, and then afterward return the set up to how you want it (IE, disconnect the Ubuntu computer from the internet, and reconnect the Windows computer to the internet.)
Or, if you insist on doing things the hard way, download the wine package onto your Windows PC from its site at
http://packages.ubuntu.com/jaunty/wine (see the download in the lower left corner -- IE, if you use a regular i386 machine, it's at
http://packages.ubuntu.com/jaunty/i386/wine/download ). Copy this file to a usb stick, and transfer it to your Ubuntu box. Then, in the terminal, run the command "sudo dpkg -i wine*.deb". It may give you some errors about dependencies. So, go back to
http://packages.ubuntu.com/jaunty/wine and get the various dependencies that are listed there, such as
libc6. Then, transfer these to the Ubuntu computer, and install (via "sudo dpkg -i libc6*.deb"). Continue this with the rest.
Another thought is that, instead of Ubuntu, you could use Debian. I suggest this because it is possible to have the full Debian, including wine and all its dependencies and libraries, available for install from DVD, or CD, rather than the internet (good for offline systems). See
http://www.debian.org/CD/http-ftp/. If you have a regular computer, than click on the i386 link for the DVD or CD images. Otherwise, click on the correct architecture of your computer for the correct DVD images.
