Download the update like the previous post said. Then transfer it to the folder called ms0SP>GAME on the system. Or if you have any umd games, it should contain a few updates that should least be able to perform wireless update.
Oh also about the security thing, You can use wpa encryption, but not aes password encryption. Or if you can find a network with no password should work too. Also you can't access psn on PSP anymore, that is no longer possible cause of sony.