Hey man, just take it to the aircon people and ask them to give you a quote that way your moving forward, just a plain re-gas could set you back any where between 60-100 then if they need to replace compressors etc you will be looking at more probably another 100-200 more. just run it down to them and they sort you out.
We do airconditioning at my work and I fixed a problem
like this on a Volvo just yesterday.
The hose could be welded(silver soldered) back together to
the piece that is still under the nut but this is only a temporary
solution particularly if there is any strain on the hose.
Cheapest solution for you would be to try to get a replacement
hose from a wrecking yard and take it with you to a/c joint.
If you cannot get a 2nd hand one then a hose will have to be
made up.
If you are running the old gas r12, you may need to be
retrofitted to a new gas depending on shop and availability
of r12.