Yes, he will always be 9 levels higher.
Did you learn the Hammer skill, and keep any skill points in reserve? That spell does damage and has a stunning effect. Maybe if you take him down some, arrows would start hitting more. Alternately, if you have the mana or potions for it, just keep going with Hammer.
Do you have any temporary boost potions?
What is your survival stat at? That helps with accuracy and initiative.
This certainly isn't the only viable build, but my hero's stats at the end of the game, with and (without) equipment, were:
Level 29
Strength - 65 (50)
Agility - 130 (98)
Constitution - 38 (11)
Intelligence - 24 (1)
Survival - 41 (19)
Speed - 72 (22)
With Bow Expertise, my hero had reload time at 12, and accuracy, point blank and piercing all at 2. The skeleton doll had Crossbow Expertise with accuracy, reload time and point blank at 1 (18 skill points in reserve)
