Im trying to amplify my wireless with my mac mini downstairs,but i dont know how.

Well, let’s assume that it isn’t the mac screwing up. The only thing I can think of to recommend is buying an Airport Express and plugging it closer to your Mac Mini, the only problem is, you need to run an ethernet cord to the Airport Express. I recommend an Express because it is much, much, easier to set up on your mac then something else.

However, I think it might be the Mac that isn’t working correctly. How far away is the mini from the router and how many walls\ceilings does the signal have to pass through?

well its upstairs and my mini is downstairs,so id say about a good 600 square feet or so

That shouldn’t be enough to stop the signal.

Have you tried switching the wireless type? I.E. from “G” to “N” or something like that? I know that my Macbook Air can see some networks, but not connect to them. I get the same thing, “Connection Failed.” That happens on my iPhone too.
I get that error whenever I switch my Airport to 802.11n. I have to use 802.11b\g compatible in order to have all the computers and phone in the house connect.

Sadly I do not know how, if even, you can change the signal type\strength on a Netgear. I personally would just start poking around in the router to see if it is possible. But if you are not familiar with doing things like that, then I would advise against it, as you can mess up your entire network really bad if you screw up!

i also have a printer that says ethernet/801.11 wireless or something like that,does that mean its a router or does it mean i can print wirelessly?

Open up Safari, type 192.168.0.1 in your address bar. it’ll ask for a name & password which should be admin/password (unless you’ve changed it). From here you should be able to find the ‘Wireless Network Mode’ (on a linksys its under the general Wireless tab) and you’re probably going to want to have it on a mixed mode unless you know everything thats going to get on it will be using N (or all G).

If that fails, unplug your modem & router (from their power supplies), wait about a minute, then plug in your modem, wait a minute, then plug in your router. This is a soft reset and should probably fix it.
Worse case scenario – buy an airport express lol

Put an airport express in the middle between your computer and your router. It can extend our network and strengthen your connection.

Get sober, then try.