If you're already 30 then not much you can do, just play until 31 and retire, or respec
I'm not an expert in throwing builds, but as an example for 21/15 maybe:
Strength: 21
Agility: 15
Hit points: 56
Skills to attributes: 2
Ironflesh: 0
Power Strike: 7
Shield: 5
Athletics: 5
Riding: 0
Horse Archery: 0
Power Draw: 0
Power Throw: 7
Weapon Master: 5
One Handed: 124
Two Handed: 1
Polearm: 1
Archery: 1
Crossbow: 1
Throwing: 100