Let's see... you are level 19 with 24 skill points... I think you only missed three free skill points from before the Battle Tower (but some are really hard to find), so you're not in bad shape point-wise. Enemies should not be doing 500 points of damage at any point, although the damage from multiple hits of Magic Blast can stack up quickly.
I would get your Strength up to about 50 or 60. That will help boost your melee damage AND your health regeneration. No more into Intelligence or Spirit. The complete warrior set from the expansion will boost your strength by 20-30 points, which is why I want you to keep your Strength that low for now - so you don't waste points by hitting the cap.
Put skill points into Dual Wield, Battle Rage, Life Leech, Bleed. 1 into Whirlwind and Rush Attack.
