Hi,
You can request a license key from the Service Market Place.
http://service.sap.com/support
Login here and click on the tab which says Keys and Requests.
Here you can follow steps mentioned in the below document and request a license key.
https://websmp210.sap-ag.de/~sapidb/011000358700000276902009.pdf
You can also request a temporary license key and start the installation till you get the permanent license key:
https://websmp210.sap-ag.de/~sapidb/011000358700000213152009E
Hope this helps.
-Nagendra