It kind of sounds like you're already doing this, but combined arms work wonders. A chokepoint with overhead archers won't kill the goblins, but it'll leave them in a lot of pain-- easy picking for your melee dwarves. Even with bone bolts against iron armor.
Copper and silver don't make the best edged weapons, but they make great blunt weapons. If you're having a lot of trouble with early melee dwarves, you might consider warhammers for them (instead of whatever edged weapon you're having trouble with). In the long term, I prefer edged weapons against goblins, but strategy really has to depend on the map, and there's nothing wrong with developing your strategy in stages. This goes for weapon traps too-- a line of silver gigantic spiked balls will do wonders for thinning out the herd.
Alternatively, you could just say, "Screw the military," and go for an early cage trap defense. On my current map, that's what I'm doing (but really, it's because I need a lot of caged goblins for something I'm working on). All I had metal-wise was nickel, but I got my first forge and smelter up early, and a single furnace operator/blacksmith was more than capable of keeping up with the need for cages (I have over one thousand cages now, about half of them full). If you don't need to save the goblins like I do, a mass pit works wonders for freeing up cages. Remember, after you capture them, goblins will just try to leave via the map edge, so if you haven't got the military to kill them, you could always just let them go.