Connect several LAN via an Access Point or Bridge

I’ve got a router at a central point in an old building. We have got several rooms in the building with their own LAN. We need to connect these LAN to the wireless router, wirelessly, to get internet access. What kind of equipment do we need, is it an Access Point with Bridge capability? I bought this box (ASUS WLAN 125 Mbps Access Point High Power 5-in-1 Wireless Access Point (WL-320gE) but didnt get it to work the way I wanted.

Any suggestions?