Printers and modems often do not work very well connected via a USB hub. They work even less well if both are connected via the same hub.
You are better with the setup you have already and if you need more USB ports, buy a USB PCI card which will give you 4 or 5 NEW USB ports.
Do you have a problem with your broadband speed? You can check and compare it if you click here and look top left aand click on "Speed Test".