Like new in the box- it would move for the $500- $575 range at your typical gun show. If it's worn or no box you'll probably see less. I've seen some for sale in the $700 renge, but they're not selling.
The accessories are typically not going to be worth much- most buyers expect this stuff to be tossed in on the deal. Unless it's something by a custom maker or desireable. And sisne the Colt is pretty rare, there's probably no secondary market for it.
The pistol is a Colt and it's rare so that makes it somewhat valuable. But they're rare because they didn't sell well and were discontinued after just a few years.. I don't think there's anything wrong with the piece, it's just a very competitive space and there are alot of options in that price range. Most guys looking for a premium piece end up with a custom pistol.
As far as where to sell- Gunbroker.com or gunsamerica.com are two possibilities. You'll likely have to find a local FFL holder to ship it through since many receiving FFL holders require the weapn to be shipped via that mode, even though the law does not require it. Local gun shows are a good way, but in this tight economy, you see virtually no dollars trading hands- at least at the one's I've been to lately.