I missed it as well. No idea where I was supposed to pick it up in the Temple. However a crafted bow is generally better - the only case where it isn't is if you're fighting something large like a dragon where all of your arrows can hit the target.
As far as crafting goes, it actually isn't as grindy as you think. I've crafted a TON of items for myself and my companions, and I never had to go out of my way to farm materials. I simply used all of the stuff I already collected from picking up ore and special crafting materials from various monsters.
The only thing I would recommend is that you get the highest DPS bow schematic - either the Swan Longbow, Masterwork Spiked Longbow, or Knight Commander Longbow. As far as I know, 2 of these are randomly found in tier 3 chests, and the Spiked one is in the Hissing Wastes, in the Tomb next to the Sand Crags camp.
Also, make sure to pick up the Hidden Blades Masterwork - there's 3 different materials that you can use:
Velventeen: 10% chance with 3 added hits
Ring Velvet: 10% chance with 4 added hits
Plush Fustian Velvet: 10% chance with 5 added hits
Here's what my bow looks like for reference:
