I agree with the previous post. If you think it is necessary to take the cat to the vet, do so. Also, after the cats vomits, hold off on the food. Second, brushing and combing on a regular basis helps BIG time in preventing hairballs!!
The Hill's company was not happy with me when I wrote them that when they were touting their hairball food. Brushing and combing give you great quality time with the cat. All 8 of our cats LOVE it!!! Good luck with your new cat!!