Line in/Mic

I've got a turntable, amp, laptop and Cooledit.

I want to copy some LP's to the laptop to burn to CD.

When I connect the tape phono cable input to the mic socket on the
laptop the recording is too loud. I can't attenuate it enough but I
don't have a line in socket on the laptop.

Is there anything I can do?

- external USB sound card? - any recommendations