Take it to a gunsmith. I've been able to remove them a couple of times in a lathe, by pushing a rod down the bore with the lathe tailstock, but it's fairly like the barrel will have to come off. If so, the extractor might become victim and possibly the bolt nose. Or just send the whole gun to Remington instead of a gunsmith. Why do you feel the handle came off?
Was there any bolt lift prior to it breaking? Did it break against the cam or completely down in the locked position? Did it break at the solder joint?