Egads, man, I am sorry to hear that! Stock up on beer now and remember, if you punch a hole in the wall you then have another patch!
A to Z rentals has always treated me nice for all my rental needs, but I don't know if they have an East Valley location. My advice for low prices/deposit and ease of availability: Home Depot. Their equipment is fairly new, they have locations everywhere, and when I asked a buttload of questions about a welder I rented they were very helpful.
I would get a 60lb chipping hammer for this job. Make sure you get one without a twist-lock plug or else you'll need to buy an adapter for use in your home. If you use an extension cord, go 12 gauge, 50' only or you will be running back and forth tripping the breaker more than you'll be chiseling.
And don't forget to wear gloves picking up the concrete pieces, or your endeavors will become much more difficult as you try to chip and clean with stitches! Did I mention make certain you stock up on the beer? LOL