uncle jimmy, you've got a couple options, it basically depends on what you want to spend. granted with your set up you're not going to realize the full potential of the benefits of laptop recording (ie. 24-bit and 96khz of more). you're also going to spend a lot on a laptop, batteries, and the sound card (input). are you sure this is the route you want to go? if i were you i'd probably either get the dat fixed, get a jb3 and a converter box to go from coax to optical, or if you've already got a laptop and enough batteries to last throughout an entire show, then you've got more options.
basically if you were to go the laptop route all you need to input sound is a device that accepts a digital coax signal, this can be done with the vxpocket v2, a usbpre, audiophile usb, or edirol products which are known to not be bit perfect like the ua-1d or ua-5.