The in-game name is already done for you (it's held by the variable "Name"). Line 58 retrieves the actual in-game name (as the function clearly says).
As it is you get this html:
Code:
<iframe src="https://united-gamers.net/in_game_signup.php?username=STEAM_ID_IS_HERE&steam_name=IN_GAME_NAME_IS_HERE&pass=PASSWORD_IS_HERE"></iframe>^n<h2>Sign up complete!</h2>
Also, there is no need to use an iframe. Just use only the URL.
As for the Steam login name, when you add friends you only see the Steam Friends name.
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