The IP address you have mentioned ar private IP address from the RFC 1918. What this means is that you can use them inside your Lan and they are not routable to the internet.
Inside your network you can use them and the econet 3G router can automatically nat them so that you can get internet access, it can also provide dhcp.
Now its up to econet to provide you with public or private ip address. With the number of clients econet have, l can easily assume that they ar giving out private ip in the 10.x.x.x range.
If you want to access you local lan for ftp or other reasons, you need a static public ip which you can from econet bt it will cost you some serious cash.
If you hav a very good reason you can buy one from Afrinic with the help of Econet, powertel or Telone.