OT - question for the computer experts

All you need is something like a D-Link model DSL-G604T/AU modem. It is both Router and Wireless so that you can use another computer (or as many as you like) with a wireless card generally anywhere in the house still retaining your hardwire ADSL connection to the main computer.

Change to a wireless modem on your existing ADSL ? - such units can support multiple users in your environment (as I recall that is - I have Bigpond ADSL wireless here at home - I'm the only user but recall being able to declare other users when doing the setup).

Yes, the setup your looking for is pretty common in most households where a laptop exists.
You do not need to change you ADSL plan at all.

You will need a wireless router to plug into your upstairs modem (just check the one you have is not already wireless - it will have antennas if it is) and you will need a wireless card/adapter for the computer downstairs. These can be a USB adapter or a card that is inserted into the guts of the computer (its not rocket science installing them).

You can buy wireless router and adapter packaged together to save a couple of dollars.

They are not too difficult to setup - often your ADSL service provider will assist you with any problems if you cant get it to work yourself (or any teenager)

good luck.

Hi Oz boc, The short answer is - yes. I believe you need a wireless adaptor for your downstairs pc, and change your upstairs modem to a wireless network modem. Your upstairs pc plugs into the wireless network modem, and your downstairs pc has a wireless connection to the same modem. I have recently changed to this set up but not without problems. The first lot of hardware I bought didn't want to work with my main computer and caused a lot of stop errors. I struggled with the problem for about 8 weeks, then the friendly computer whiz who lives two doors up came over and sorted the problem out in 5 minutes!- He ditched the wireless modem I had bought(a D-Link) and installed a Netgear one, hit a few keys, the computer flashed a few configuration screens and presto- all done! I would probably pay a computer 'whiz' to advise you and set this up for you.Cheers.

Agree with all of that. And I would add one other thinng. If you have an ADSL connection, check to see if you can get ADSL2. If you can, you might as well save a small fortune by getting a VOIP telephone set up through the same connection. Several of the wireless modem routers have this built in so you might as well do the Voip connection at the same time. We use a Netcomm NB9W wireless router. It has worked just fine. (Check, they don't all have this built in) We keep our regular phone number and it works through our ordinary phones.
Once running, it's easy. The only difference you would notice to a regular phone is that you need to dial in the state prefix before every call. Local and interstate calls. Unlimited timee and about 8Cents. Overseas calls usually about 3c a minute.
But I would get an expert in to set it up. We Use Jim's Computer support (in SA. Other states??)(the same franchise operation as Jim's Mowing) and have found their computer service to be excellent and very reasonably priced.

Plustec
That's interesting. Ours has been bulletproof. I don't understand why it would cost $400 to return to the old system. If I wanted to go back, it would cost me nothing. You must have a very different voip setup to mine. Do you know if the problem is in yout ISP or your Voip provider? I am using Adam internet for the ISP and Smartvoice for the Voip. Check Smartvoice prices. I use my regular phones. If voip ever went down, the system would just revert automatically to a standard line.