What he said.

If you have a place that can make hydraulic hoses near you (our local O'Reilly's makes them), and you have one of each end you need, they should be able to put a new hose on your ends.

As far as I know, they don't make any adaptors to change from one size set up to a different one. I've had several hoses made up to attach specific pumps and steering boxes together. Swapping between different manufacturers pumps and steering boxes nearly always requires specially made hoses, its usually the cheapest was to go. Another option is to buy a hose that has one end correct and take the end of the other hose you need with you. and have just the one end changed.

When ever you want to change the hose ends, be sure you take in the ends with the rubber connection still attached, there are hose barbs on the ends of the steel lines that have to be reused to hold the pressure.

That said, it may be possible to change the fitting end in either the pump or the box to solve the problem. I'm pretty sure when the hose ends first changed they simply put in different fittings into the pump, or at the box.