Can I swap my Saccon Altex calipers with Campagnolo Veloce
The pull will be fine if those are the levers you have. You should measure the reach needed by your bike. It's the vertical distance from the center of the brake hole to the center of the brake track. Veloce calipers are 39-49mm.

Doing this with Campy is suboptimal because you won't have brake quick releases anywhere.

Not much can happen to the sort of brake you have to make them truly beyond repair. If normal cleaning/lube and adjustment doesn't do it, they may need their springs bent.