Extending network AND LaCie NetworkSpace2

Hi Guys,

I actually have two questions with one common factor. My Airport Extreme.

So here goes;

I want to extend my network at home with my Airport Extreme but am having some trouble with it. To make things clear let me just start with a quick explanation of my setup just to give you an idea.

I have the wireless router provided to me by my provider plugged in and acting as the router it's supposed to be, then I have my Airport Extreme setup in the same room and is connected to my wireless router by ethernet cable. (I have this setup because from my Airport Extreme I have my Xbox and TV connected and this won't reach my regular router).

I have configered my Airport extreme to "create a wireless network" and have been carefull that the settings are exactly the same (passwords, type of security, same name for network, and radio mode). However I'm having a lot of trouble connecting to the internet (only my apple products), I frequently see two the same networks but have to choose one of the two, lose my connection quite often and my AppleTV suddenly wont connect anymore. I'm not sure what I'm doing wrong but I hope someone can help.

Secondly I have a LaCie NetworkSpace2 connected to my AirportExtreme but this will also not connect even though I can "see" it in Finder, I keep getting the message "connection failed". Now I'm quite sure the one problem has to do with the other but thought it would be handy to mention.

Hope someone has some answers for me and I hope I've been clear enough...

I've added a picture which will hopely make it even clearer.

 

I bought it about two years ago but the software is up to date.

 

I've also done a factory reset but it doesn't seem to make any difference.
Some of my apple products get on the internet and some don't. My wireless network is showing as available but I'm unable to get online.

Would it be wise to otherwise shut-off the wireless capabilities of my router (the one provided by my provider) and only use the airport extreme to host wireless? The area that I'm trying to cover shouldn't pose a problem.