You should be able to plug the keyboard from your desktop computer into the laptop. Vista will recognize it via PnP, and you don't need to turn off the laptop keyboard in order to use it. If it's a serial keyboard, you may discover that many laptops don't have a serial port; but you might get lucky.
Note that on the "real keyboard" the Alt-NumPad method of entering character ANSI codes doesn't work until you turn on NumLock. The NumPad on real keyboards is an "Arrow Pad" with NumLock off.
My laptop doesn't have a NumLock key (that I can find) but the Fn key automatically switches the "embedded numpad" on with NumLock "always on." Note that the Fn key must be held down continuously to use the NumPad continuously – at least on my laptop.
Since there's no display of the keys pressed with Fn-Alt pressed, I found it somewhat difficult entering Fn-Alt-NumPad characters correctly without more practice than I'm willing to do; but the method does work for me.
I did IMMEDIATELY notice that Alt-Fn-#### doesn't work on my laptop.
I MUST press and hold Fn and then press and hold Alt, and both of those must be held down until the numbers are all entered. If I press Alt first, and then Fn, I get nothing, even if I hold them both down while entering the numbers. It might be worth checking whether the laptop you're using accepts "either order of entry" or just to make sure that it still doesn't work when you do them strictly in order.
For some older Windows versions, "leading zeros" were ignored by the Alt-NumPad method, but that's not quite true for Vista. If I type Alt-128 I get a different character (Ç = hex 00C7) than if I type Alt-0128 (€ = hex 20AC). (Microsoft has "mapped" ANSI 128 to the € euro on US keyboards, but may have done something different elsewhere for keyboards with a key for the €.) It's probably safest to always use "four digits" for Alt-NumPad entry now. There are a few other "shortcuts" implemented, rarely well documented.
IFF your wimp-Word does the hex code Alt-x thing, that's probably the easiest method if Alt-NumPad really doesn't' work. If you have a Word document with the chars you want in it, placing the cursor immediately to the right of a char and hitting Alt-x should show you the hex number for that char. If you type that number elsewhere and immediately (without spacing etc) hit Alt-x, you should get the character.
Early Works Word were little better than DOS COPY CON >, but what came with Vista Home Basic was reportedly very much like a recent obsolete version of "real Word." I just can't remember which Word version they claimed it emulated. Try an Alt-x with your cursor anywhere in a Word document. If anything changes, it probably works. Even a blank space is hex 0020.