Ok.
I bought a used but never ridden 1989 Bianchi Giro last week. Campy grupo. The 7 speed freewheel has a range of 12t to 23t and the front cranks are 42t and 52t respectively. I live in the rocky mountains and the gear ratio is killing me on all my local climbs. I want to switch out the freewheel for something with a range of 14t to 28t.

What are my options?
The vintage Reginas online are prohibitively expensive, and I have serious compatibility concerns with installing a shimano, suntour or other brand freewheel.

Are my price expectations on the reginas unrealistic, and are my compatibility concerns regarding putting shimano freewheel on a campy drivetrain and wheel justified?

Thanks