How can I connect crossover cable?

Hi,

I am a newbie. I want to connect my Inspiron notebook to my desktop for transferring files and share the Internet as well. I use cable Internet. My desktop has LAN card and my laptop has a LAN PCMCIA. I only want to connect these two computers. If I want to use the crossover cable, the question is the LAN card on my desktop which is connected to the Internet has only one socket which is used by cable modem wire. So how can I connect the crossover cable to it? Should I buy anything else?

I am really sorry for such a simple question but your answer is highly appreciated.

Armand