Best area to live in Rome with young kids

My husband has received a job offer from the FAO in Rome, and we're considering moving there at the start of next year. We have two kids, and we'd likely want to enrol them in the American international school as his contract is only 2 years, and it doesn't seem worthwhile to put them in an Italian school. Can anyone recommend a good area in Rome that would be ideal for families and in close proximity to the school/work. We haven't decided if we're going to get a car yet, is this a must?