I think our members here are slow to respond to your post because the "Caurus" model is virtually unknown on this side or the pond.
I am no expert on Bianchis but I did a search, and found a reference telling that the near-equivalent US model would have been the Bianchi Premio, which was an Asian-made Bianchi equipped with Shimano.
As such, I would guess its value would be in the 200-250 ballpark.
Now that I've thrown out an dollar estimate, someone here will slap me down if I'm wrong, but I base my estimate in part on my Italian-made Cd'I, which I am pretty sure would get about 350.
It would help if you could confirm a few things:
Firstly, it looks like it has a Shimano Biopace crank and Light Action DRs (?) - They look like Diacompe stoppers and I don't see a trace of a Columbus label, so I assume that it's Tange. If so, that would tend to confirm its origins, and market value.
PS- In reading owner's comments about their Premios, it seems that they are well liked as riders. (That does not surprise me - any Bianchi is a nice ride.)
__________________
- Auchen