What are you talking about? You're statement isn't making much sense. So, you have a WiFi wireless router. It's all setup with a wireless network, and everything. Then you connect your laptop to the router via Ethernet cable and it all works. But when you unhook the Ethernet cable, it doesn't work? If that's the case, then you don't have the WiFi setup. You should be able to connect to the router via wireless with your laptop provided it's setup correctly, and you have a WiFi enabled laptop (standard these days).
What I would suggest you do, is connect your laptop to the router, and configure it from scratch again. Setting up wireless networking, etc.
Then Disconnect your laptop from the router, eneble your wireless on your laptop, and connect to the router over wireless as per the settings you specified when you setup the router.
Your router should have the WAN / Internet / External (all depends on brand of router as to how they lable the connection) cable connected to your xDSL / Cable Modem at all times.