Internet Connection Sharing on a Wireless Enviroment

I have got a wireless connection through a PCMCIA device for a 3G connection that I wantted to share with computer around the house. For that I bought an access point/router and which is connected to one of the desktops via cable as it does not host a wireless interface. They can all comunicate on the LAN/WAN enviroment however when I share the internet connection on one of the wireless Laptops it does not work (no other computer can access the internet). Can anyone help?

Thanks very much