How can I boost my CL..

[Nameless Void]

At level two to have a Caster Level of 5 (to qualify for a Prestige Class)

Any ideas?

[sirpercival]

Primitive Spellcasting or Elder Giant Magic feats.

[Agnostic Paladin]

Is there any first level spell that has no verbal, somatic, or material component that would work for Primitive Spellcaster? Getting Elder Giant Magic at Level 2 is going to present a larger problem than a 3 CL boost.

How about Practised Spellcaster for a 2nd level wizard who's using a 3HD (or more) base creature?

[Jackinthegreen]

Is there any first level spell that has no verbal, somatic, or material component that would work for Primitive Spellcaster? Getting Elder Giant Magic at Level 2 is going to present a larger problem than a 3 CL boost.

How about Practised Spellcaster for a 2nd level wizard who's using a 3HD (or more) base creature?

A 2nd level wizard with 3 racial hit dice (and no LA) is a 5th level character.  This is explicitly a 2nd level character.

[Ithamar]

Feather Fall has only a verbal component.

[sirpercival]

This may help.

[Agnostic Paladin]

Feather Fall has only a verbal component.

Well, if we could get it Silent without increasing the caster level, Primitive Spellcaster could be used to add three to caster level. I was thinking Arcane Thesis, but again, the skill prerequisites remove that from consideration. If this were for Pathfinder, a deaf Oracle treats all her spells as Silent for free - other than that I can't think of any way to get it Silent for free.

sirpercival's list is much more likely to meet success than a large feat stack.

[sirpercival]

Particular class & race combos can help you as well.  For example, a Dream Dwarf Cloistered Cleric with the Knowledge & Oracle domains always has a CL of 5 for divination spells at level 1; if you need arcane CL, then take a level of Diviner at level 2 and you're fine.

[Maat Mons]

Is there any first level spell that has no verbal, somatic, or material component that would work for Primitive Spellcaster?

Divine inspiration (Book of Exalted Deeds) and secret signs (Complete Arcane) fit the bill. 

[Nameless Void]

Wow, thanks for all the assistance guys!

Does qualifying with one spell count towards: Arcane caster level 5th?

[Agnostic Paladin]

AFAIK, by RAW it does count, but I'd run it by your DM first to be sure.