Cisco 1720 Router setup with D-link wireless & cable modem for home

I am working on a project for work via my home network. I want to use a Cisco 1720 router with my 2950 switch, but what interface to I use to connect my cable modem to the 1720? Also, I still want to use my wireless d-link router for a wireless lan, but how would I get it to work with the 1720?