If you're a bit of a DIY guy, you could try fixing it yourself. it can't get any worse than it is. What you have to check is if the grinding noise it makes is present when it compressor is engaged or when its off. if it makes the noise only when its off, then it is possible that the clutch plate in the compressor is faulty. I don't know of the exact name of the part but it functions as a clutch plate so thats what i called it. if it makes noise both when engaged and disengaged, then there could be much more at fault with the compressor. or it could just be a bearing. You could go to a scrappie and get another compressor and fit it yourself. its just 2 bolts holding it to the mounting and 2 pipes. it should have just one wire to it. once its fitted, you can get it regassed and make sure you put some compressor oil with it as a compressor from a scrappie would be devoid of oil. fitting the belt shouldn't be a problem either. you can leave one of the adjustment bolts on the compressor loose to allow the belt to slide on and using a crowbar or a long metal pipe, apply tension to the compressor while tightening it. I've done it before on a Toyota Camry and it takes under an hour. I'm not sure of the exact location of the compressor on a V6 accord but you might have to take the radiator out for ease of access. If you devote your saturday or sunday morning to it, you should be able to finish work by noon the same day.
Repairing the compressor might turn out more expensive than replacing it. get a nice clean one from a scrappie and you should save a fair bit. Ask the mechanic how much he will charge for replacing it if you got another one and work out the costs to see if its feasable for you.