SAP Enterprise Portal License

Dear Experts,

We are running SAP ERP6.0 ABAP EHP7 and Solution Manager, now we would like to go for PORTAL for HCM(ESS & MSS). I want to know SAP- Enterprise Portal(PORTAL) license structure(includes what tools etc) and procedure , is it for free or do we need to pay a little more in the existing license ? or we need to apply for a PORTAL license separately.

Please give me information on this or any relevant contact who can help me in this regard.

Kind Regards,

Domnic