It seems as if you don't want to buy the iBurst Modem, but buy a router instead?
That is impossible.
The iBurst modem is the only way you'll connect to their network.
Without the iBurst modem, you will not connect to iBurst, period, and yes, get the desktop modem instead of the USB devices, they get much better signal.
The only thing that the Router will do is split your internet wired and wireless to other devices which are plugged into it.
Any brand of router will do the Job, iBurst is not dependent on your Router...