Question : Adding a wireless router to an existing network

I work in an office, here is our network layout: Linksys Cable/DSL router > Upstairs - Netgear 16-Port Switch > Office Computers.

We were wanting to add wireless capability to our system, so I brought in a D-Link DI-524 Wirless Router.  Upon plugging it in, it immediately saw the internet connection and seems to be working.  However, the router seems to be on a different IP / Gateway scheme (office = 192.168.102.1 | wireless = 192.168.0.1), the issue I am having is, our network cannot see the wireless computers on the network although they have the same workgroup name.

My hope is to turn this wireless router into a wireless switch, or access point working from the original router DHCP instead of implimenting its own.  Whenever I attempt to make these modifications to the wireless router, I lose internet connectivity.  

I searched before posting this, but found only people suggesting they purchase other equipment.  I would like to make my current equipment work, if possible.

Answer : Adding a wireless router to an existing network

You can make your D-Link DI-524 an access point quite easily.
-do not configure anything on the DI-524's WAN page
-On the LAN page assign it an IP in the same network as your existing local network for example 192.168.102.254
  Make sure it doesn't conflict with any existing devices or your existing DHCP range/scope
-Disable DHCP on the DI-524's LAN page
-connect the DI-524 by inserting a patch cable between one of the LAN ports (not WAN) of the DI-524 and either a LAN port of the Linksys or your Netgear switch. Leave the DI-524's WAN port empty.
-configure your wireless and security settings such as encryption

Now any devices connecting wirelessly will connect to your existing DHCP server through the DI-524, get an address in the same subnet, and be able to connect to the Internet through your existing network/hardware.