Cannot access the internet but wifi point is active on my WN3000RP.

I have just purchased the WN3000RP. I have set it up via pairing function all functions are green as they should be and seem to be working. I am able to connect to this device and the signal is 100% but that is as far as it goes. I am trying to connect our PS3 to the extender but as soon as I go to the internet connection it will not connect to the internet or anywhere that I can use the wifi extender for that matter. I can however still connect to our original modem at 40-50% signal, which does not help as the signal is not strong enough. The extender is in the list but anytime that I try to connect to it it just won't happen. I have put in the password of my own modem as it has said to do but it tells me that it is incorrect. I have tried manual loading of connections but this is the same result. It asks for the WEP Key which I thought was my password but still no go. I am having the same problem trying to use the extenders wifi on my Samsung S5, it will connect to the extender with 100% signal but as soon as I go to use the internet it tells me there is no internet. Can anyone help me please.