Connectify is an easy to use software router for Windows 7 computers. After downloading and installing the lightweight application, Connectify utilizes your computers' built in Wi-Fi card to wirelessly share any available Internet connection: a cable modem, a cellular card, or even another Wi-Fi network. Other Wi-Fi enabled devices including laptops, smart phones, music players, and gaming systems can see and join your Connectify hotspot just like any other Wi-Fi access point and are kept safe and secure by password-protected WPA2 Encryption.
I certainly hope it is not using only the "built-in Wi-Fi card". Something to try out.