My question is, have you tried just going to the Internet Browser to actually test the connection?
Network > Internet Browser
If you have done that and it's still not working, then you may need to change the connection type. If it's wired, make it wireless or if it's wireless, make it wired and see if changing it that way helps.
Another thing you could try, and some people have gotten it to work this way, is to completely turn off the PS3 by the back power switch, wait about 5 minutes, then turn it back on and test the connection then.
From there, if that's still not working, then you may need to set the IP address on the PS3 manually:
Settings > Network Settings > Internet Connection Settings > Custom
Then when you get to the IP Address, select Manual and input the necessary information.
You may need to reset the router one or two more times throughout this process jut to make sure it properly connects.
Finally, if that's not working, then there may be something else wrong and I would be at a loss without actually being there to work on it myself as I've never had problems connecting after following these steps.
So good luck!