I would suggest a
Modem -> router -> wireless AP
or
Modem+router -> wireless AP
Best if you can get a router with USB and Gigabit ethernet. This way you can also connect your external hard disk and printer to the router.
The wireless AP will serve as your wireless access to the internet. Since the AP is designed for multiple users/connections (should be able to handle at least 30 users) it will be able to relieve stress on the router. Routers typically have a built in AP and it isn't really designed for multiple users/connections.