Keep Access Point outside of network?

[c1001]

I am running a NETGEAR FVS-124G router and am looking to add an Access Point to provide wireless internet access to the other side of my house and for visitors. Is there a way to add an AP to provide internet access while keeping visitors outside of my network (so that they can't access shared folders, NAS, etc)?

I don't want to password protect the NAS and shared folders because then my wife will nonstop forget the passwords.