Hey, I've just started biking in the last few months, but i've noticed that some riders wear "booties" that cover their shoes with a cutout for the clip-on pedals. You should ride down to your local bike shop and ask about them. I usually just wear two sets of socks, which also works. Depending on how much room you have in your bike shoes, you may want to look into the "booties".

Oh, I see. I thought the numbness was due to weather. If your feet are getting numb (not cold), it is probably due to vibrations. I have the same problem in my left hand. Maybe you should look into a more comfortable shoe.