Funny acceleration noises after running over a truck tire?

I have an '08 PT Cruiser and got behind a turck earlier today to exit the freeway only to see one of the layers of his tires come flying out from under his trailer and although I tried to avoid it, the tire piece went under my passanger side front and tire. I pulled off the freeway, popped the portion of my bumper and liscence plate back into place that the tire had knocked out and now when initially accelerating, I can hear a loud gutteral sound coming from the car but it goes away in seconds unless I accelerate hard again. It does not make the sound when accelerating in park, only in drive. It is not leaking any fluids save for a slight water drip from the AC. Any ideas what this might be or how much it might cost to fix?