A/C work is something you might want to leave to expert one due to the lack of proper tools.
First, you should recover the refrigerant if there is some left (ozone layer!).
Then you have to replace the hose. you can't really repair. The only way to repair would be to remove the hose, repair and put back. You'ld save some buck, but it's a bad repair, if it even work.
Whatever you did, you then need to vaccum the system. But before that you probably want to replace the receiver dryer...
Once all vaccumed, you can fill it back. You might have to add some oil, or not. Adding oil when not needed can damage the compressor. Lack of oil will damage the compressor.
Then add the right amount of refrigerant.
More info from EricTheCarGuy video:
http://www.youtube.com/watch?v=95RdGLFIbL8
http://www.youtube.com/watch?v=lglPJuBXVeE
Notice that he tried to repair, and it failed... aluminium is close to impossible to repair....