If you feel you can add the ips on your own here are the instructions. If not you can open a ticket as Preacher said, and SM will add them for you.
Open your network connections
Right click on Local Area Connection and click properties.
In the top window highlight Internet Protocol (TCP/IP) and click Properties
From this page click Advanced bottom right.
Top pane show your currently assigned IPs. You can simply click the add button and type the next IP in. Make sure you use the same subnet mask info as the first one uses.
Should be it.