New bike vs. new components
I hope it's not annoying that I've now started a bunch of different "help me!" threads; I'm new to all this, so I hope you'll forgive me.
Anyway, I like my bike. It's an early 80s Reynolds 531 Trek. It's light and peppy, and it fits me pretty well. I'm told it's a nice bike that I got a really good deal on.
I'm training for a century in the fall, and I'm either going to have to switch out some components on my bike (headset is the big one, but I'd also want to probably upgrade some other components and get a new saddle) or get a new bike better suited to a longer ride like that. My budget is between $500 and $900. I'd like to save money where possible, but I'm willing to spend money if it's going to be worthwhile.
So what do you think? Should I start looking at new bikes and keep my current one as is for city riding? Should I hit up a bike shop and tell them to pimp my bike?