OP...you can easily go either way on this. Older bikes like a vintage Lemond either have sentimental value to you or not. If not, then you can be more clinical in your approach. If you Jones for a new bike, don't look back...sure will be easier. If you want to upgrade your Lemond, then ebay is your friend...gene pool for used and new bike parts. If you keep the bike, take it on as an opportunity to grow. Buy a bike stand and swap out parts yourself. Do research like you have started and find out exactly what you need and get it off ebay. You would be further ahead to keep the bike 9 spd and find shifters and any odd parts that you need. Piece meal off ebay is many times cheaper than buying an entire gruppo. You could even turn the bike into a fixie, townie or single speed. Lots of options and no single solution other than how you feel about it.
Have fun.