The username is XXXXX XXXXX If admin doesn't work for the password, that means someone has changed it. You can try guessing passwords but if you can't figure it out we will not be able to retrieve your key from the router.
If you have any other wireless computers that are successfully connected to your network, you may be able to get the keys from them. If not, you'll have to do a factory reset on the router which will reset all the settings and remove the encryption and you'll have to set it up again. If you want to do that, lte me know and I'll give you instructions.