Barrage doesn't have AOE, so the only way to increase it's range is to get closer to the target, or have the target get closer to you.
this is in an old post with the ranges of the different skills. hope it helps.
Increased ranges of projectiles to surpass ranges of other non projectile abilities:
Barrage - 25yd
Comet - 25yd
Pierce - 25yd
Arrow - 30yd
Bullet - 30yd + Additional Bullets
Hatchet - 25yd
Thrown Sword - 25yd
Rock Blast - 25yd
Teleport/Shatter - 20yd
Blink - 20yd
Swap - 20yd
as an example to help, Comet has AOE, and Barrage doesn't, so someone with Comet can stay out of the range of the person with Barrage and hurt them, because of the AOE. but that is if the person with Barrage camps and doesn't move.
this came from Patch 2.0, so I don't know how accurate the ranges are or if there have been any changes.