Instructions
Select "Settings" from your PS3's main menu. Choose "Internet Connection Settings" from the "Settings" menu.
Select "Internet Connection Settings."
Select "Easy" when prompted to choose your setup style. When asked to pick between a wired or wireless connection, pick "Wireless." Choose "Scan" to view a list of available wireless connections.
Select the listing (by highlighting it and pressing "X" on the controller) for the wireless network with the bad signal that you want your PS3 to connect to. Select the type of security that is in place on that network followed by its password (if applicable).
Select "Save." Your Sony PlayStation 3 is online, even though the wireless network has a weak connection.