There is No combo Modem/Router the worth much more than a "Dime".
These type of devices were invented to be as cheap as possible by the ISPs.
It cost the ISPs much less to give a free (or low cost) combo than the cost of the Millions of TechSupport calls needed when the Connection's authentication is done by computer software installed on computers of ignorant End Users.
When the connection is kept alive through firmware on the WAN side, it neutralizes the weak link
of the System (the users
What to do?
If your current combo can be configured as a Modem only, do it and get a good Wireless Router.
P.S. One should know that No Wireless Router can stand to an Extensive "hassling" of the connection with torrenting).