Adjustment to W-4 now that my daughter is no longer a dependent

Hi. My daughter just finished college and is supporting herself and we no longer claim her as a dependent. As a result, we got walloped when it was time to pay our income tax (had to pay more than $3,600 - a big amount for us). I would like some advice on how I can fill out my W-4 so that we don't take a big hit next year. Any other advice along that line would be appreciated. My wife and I file jointly. She is a minister and the majority of her income comes in the form of a housing allowance.