It doesn't really matter if you have an access point, if it is not correctly connected and setup on the network it won't give you Internet access.
You will need to describe your hardware setup more fully to get advice, and include your network settings. For example, are the modem, router and AP all on the same network; is your modem wirelessly bridged to the router and then the AP wired off the router; which runs the DHCP, the router?