Help me understand mortgage refinancing?

[Maggie]

We have about $30k in equity on our home, and currently have a 30 yr fixed at 6.9%. I'm not sure if refinancing will help or hurt us. My student loans are at 7.22, but I only owe another $3500, and my auto is 1.9% and I owe about $6500. I thought about paying those off with the cash from the refi - is that a bad idea since the auto loan is at a lower rate? I thought since the mortgage interest is a tax right off and the auto loan isnt...?

If we aren't sure how long we'll be in this house, is refi a bad idea?

I'm pretty confused about this - any help would be greatly appreciated.