Upgrading gear level

New to these types of games. I have a really cool bow I found in middle of act 1 that is level 11. I'm in act 2 now and have found nothing but dog. Really wishing I could just bring its level up to my current level around 20. Many other games seem to have this feature and from what I can tell there isn't a way to do that in this one. You just have to live with it. Kinda sucks and doesn't feel good and makes me not want to play anymore because my good bow with good sub traits is just being out scaled by the enemies. Just a thought from a new player. If this is already a thing someone please let me know.