Against Evil creatures a purely Arcane caster has 2 options
I used this advanced spell searching tool to look for wizard/sorcerer/bard spells with the [Good] descriptor. I got 16 results, mostly from the Champions of Purity splat book. Of these, 2 allow a Wizard or Sorcerer to bypass/disable Regen X/Good.
This spell fills the area with a brilliant flash of shimmering light. Creatures in the area are blinded for 1d4 rounds, or dazzled for 1d4 rounds if they succeed at a Reflex save. Evil creatures in the area of the burst take 1d4 points of damage per caster level (max 5d4), whether they succeed at the Reflex save or not.
This is a level 2 Sorcerer/Wizard spell. Since it has the [Good] descriptor, the damage it deals will bypass Regen X/Good. The targets need to be evil, but that is what you asked for anyway.
This spell functions like lesser angelic aspect, except you gain low-light vision, darkvision 60, resistance to acid and cold 10, and DR 5/evil, and you sprout white feathered wings allowing you to fly at a speed of 30 feet with average maneuverability. In addition, your natural weapons and any weapons you wield are considered good-aligned for the purpose of overcoming damage reduction.
This level 5 Sorcerer/Wizard spell is your only general-purpose option (if you find a non-evil creature with Regen X/Good). You'll need to physically hit the target with your weak Wizard arms, but the resistances, DR, and flying speed should work to keep you alive.
Oddly, Angelic Aspect, Greater improves on Angelic Aspect in everyway except it doesn't include aligning your weapons to Good.
As always when using material from a non-Core book you should get GM approval, but these are from an official source so you shouldn't have too much difficulty with that.