I rode and raced on just such a rig. You can buy brand new Vuelta or Reynolds Comp wheels for your $100-150 range, and if the current crankset and derailleurs are in decent shape, leave 'em alone; odds are good they'll work fine with indexed shifters.
Sound advice, though I think the greatest benefit would be moving to STI. I would still upgrade the brakes and brake levers if we ended up keeping the cranks and derailers, so there wouldn't be too much money savings.
It would be possible to use the existing crankset with 8 speed shifters and derailers, I believe, though the lack of ramping and pinning might make the shifting less crisp. Not really a big deal, hell, I actually run my road bike as a single.
My suggestion is to keep your eyes open for a complete used bike. Don't worry about the size, color or anything else.
Strip it and sell the frame to get some of your money back. Put the components on the old frame and be happy. Otherwise be very very patient and hope you get lucky.
That's an excellent idea! Whichever comes first, the road bike or the wheelset, I suppose will determine the build. Thanks.