IVR Prompt for Username and Password?

I am really new to Asterisk but I have successfully setup AsteriskNow 1.7 with FreePBX and I am able to authentication to a RADIUS server using the Portaone RADIUS client. I am looking for a way to prompt the caller to enter in a username and password that is stored on the RADIUS server. I am able to to authenticate now by using a softphone to dial the following extension.

exten => 1100,1,agi(agi-rad-auth.pl,Password=Test123)

I altered the agi-rad-auth.pl with the following.

$r->add_attributes (
{ Name => ‘User-Name’, Value => $input{‘callerid’}},

It uses the callerid number as the username lets say 1200 and I have a 1200 user on my radius server. I thought this was the simplest way for me to figure out how the RADIUS authentication works. I ultimatly would like to have the caller dial in from any number and get a prompt for username and password stored that exists on a RADIUS server. The password will eventually be a OTP (One Time Password) generated by a token. I think once I figure out how to capture this information from the IVR it wont be too hard but since I picked up Asterisk last week my knowledge of IVR is limited. Does anyone have any advice?

Thanks in advance!