The least expensive way to go would be to purchase an unmanaged switch - which allows the d-link router to "still be the boss". Unmanaged means that it won't have any additional configurations - it just takes requests and connects them. The next step up the ladder is a managed switch, this allows you to set priority to specific functions or computers. Then you have the router - which serves as DHCP and DNS for the network.
Brands typically don't matter - especially in the unmanaged/managed switches. Rarely do manufacturers require identical routers to create access points in a network - but I have come across a few issues.