your ISP is either blocking access to the gaming servers...not all ISPs allow you to hook a games console, check with your ISP to see if they allow such access, htey block it as it works in a similar way to P2P software for sharing copyrighted content Kazaa LimeWire etc etc
if your ISP is NOT blocking this type of access i would look at changing your router...sound like it dead or die-ing
also you say when ever you go to plug in your PS3 this occurs...I have to ask why is it A not plugged in permanetly or B connected Wirelessly ?
or do you mean plugged into the mains ?
also looking at the spec of your router...I think thats where your problem lays.
this what I use
http://www.ebuyer.com/product/120468
check this page
http://www.amazon.co.uk/exec/obidos/...1-21/ref=nosim
and look at the customer also viewed section for other N1 option