>>22567636
You won't get it until quite a while though:
You need 4 feats to get it, so the earliest point possible would be levlel 9.
Your plan should be to talk to the DM about splatbooks once you're outside the city.
Be honest about the combo you're planning, and point out that it's really powerful, but you have to pay a lot for it.
The splatbooks you want are Complete Arcane and Complete Divine.
If you're allowed, and you're playing Heironeus, check out the following Prestige Classes:
Inquisitor: You're a paranoid motherfucker who gets more skill points, social class skills and neat anti-bamboozling abilities.
Contemplative: You're really really into your God, and you gain an extra domain.
Ordained Champion: If you ever wanted to be a stomping smashing melee cleric, this is the PrC for you. But don't take too many levels, since you won't get level 9 spells if you do.
It's supposed to be Heironeus/Hextor only, but there really ought to be a Morradin version out there too.
The reason you want PrCs, is that you don't really get anything from taking levels in Cleric except spellcasting. All the Prestige Classes listed gives you the same spellcasting, and generally better stuff. Of course, you need to pass certain tests to get access to these PrCs, but that might be something your DM would approve of, since it gives him plot-hooks out the asshole.