Unfortunately, Cleric's aren't meant to tank, heal, and demolish undead and other foes alike, all in a single stride . As fun as that'd be clerics tend to compensate in other ways.
Winterstone is a great choice though, one that's fairly easy to obtain, and is one of the few weapons accessible to Clerics that deal Ice damage. I'm imaging great things for the wizard class though...wondering if it'll be more of a wizard-type or a mage-type?
Other people have told you the other possible item - although the wiki misleadingly calls it "Common", when it really should be Uncommon, as Traveling Armorers are rarely found in the first place, and then they rarely have that item for sale when you find them.
But the real answer to your question is, "there are a lot of great one-handed cleric items". When I was a lvl 10 2H Warrior, I took my lvl 8 Hirge and we somehow slugged it through Zamohr Mountains and into Castle Bluerock, sprinting through the gauntlet, and made it down and claimed the Ghostbane in our first attempt. Took me a good 10 Light Healing + 10 Medium Healing potions, but we did it. Life's easier from there.
Another alternative around similar level is to head to Kurgua Cave and find a Bone Mace (ideally, a Mystic Bone Mace), which will give you a little more firepower plus some stun, and with no elemental resistance to worry about until you get the Paladin Sword.
The Flaming Warhammer can be obtained around then if you aren't too bothered by cutting and running. You can grab the quest item necessary to get it and then beat it out of there without killing the things that are attacking you - might be more useful than Mist Hunter's Bow if you're focusing on Hirge as your main companion.
Finally, the Hammer of Corrosion is very findable by lvl ~10-11, ideally if you can clear the Abandoned Tower, but even if not (if you'd prefer to use it to clear the abandoned tower), you can sprint up to several chests in Crimson Hills and just avoid fighting the Hill Giants and keep trying till you find it (easier with Potions of Speed, of course, but that can get costly quickly).