By being human?
Divine Spell Power (Complete Divine) isn't really useful unless you can reliably score at least a 13 with a Charisma check, so it may not be the best choice for you.
Cleave isn't a bad feat at low levels, especially combined with the Strength domain's granted power.
Divine Might (Complete Warrior) will let you expend a turn attempt to add your Charisma bonus to damage for a round, which could be useful if you have more than 14 Charisma.
Touch of Healing (Complete Champion) is good, but I have the feeling your DM won't allow it, if he banned the warlock.