You'll need to have Screen Sharing or Remote Management turned on in System Preferences/Sharing first.
You'll need to make sure that your machine is set to never sleep, also if you have a dynamic IP you might want to register with http://dyndns.com What that involves is setting up a hostname, such as johnrougex.dyndns.biz, (they have different variations on the dyndns.biz per your choice) then you install the DynDns client on the Mac which stays in touch with dyndns and keeps track your IP address.
When you type in johnrougex.dyndns.biz in the screen sharing app it goes to dyndns.com and will resolve to the current IP address of your home or wherever you have the client running.
It's free, but you only get one hostname, and they will send you an email once a month to make sure that the account is still active. Their Pro account is only $15 a year which gets rid of the monthly email nag, and allows you more hostnames which you probably won't need.
You'll also need to set up your home router, or modem if it is doing routing, to forward any requests for TCP port 5900 to the Mac you want to control. Some routers call it a virtual server.
If you are getting a 192.168.x.x or a 10.0.x.x IP address in Network preferences something is doing the routing and will need to be configured.
For some reason everything after the /at/ didn't work from your end, corporate firewall maybe? It is from another country and wants to redirect to the iTunes store.
As far as the keyboard from what I understand any keyboard used to work but Apple broke that. You now have to jailbreak or get the iPad dock w/keyboard. An Apple wireless bluetooth keyboard will work too.
BTW, if you mean just controlling your Mac from your couch, and not from a remote location, you don't need dyndns and you won't have to configure the router since you'd be on a local network.
That's a different product. This is what I meant. Real VNC does the same thing but you need to install the VNC server software, kind of expensive, $50 per license, on the Mac so that the client software can connect.
As an FYI there's two parts to remoting in, the server software, and then the client client software which is what connects to the server software. iTap VNC is the client software and it connects to the built in Screen Sharing server software of the Mac.
I do use the free Ultra VNC server to control my PC headless from my Mac since there is no remote access server software built into XP Home edition. I use the Go menu's Connect to Server for the VNC client on my Mac.
There are quite a few products with VNC in the name.
Have to run out, will probably be gone until later tonight.
I have a decent one called Gamma VNC, but it looks like it has been removed from the app store. It was free. I also have one called SplashTop remote. It's pretty impressive for $4.99. It sends the audio to your iPad as well so you can actually watch videos that are playing on your Mac. The Splashtop Mac software you install is free.
EDIT: They have a free version of Splashtop that you can test. It supports connections for up to 5 minutes. Good way to test it out.