I am not sure of the capabilities of Soundbooth, but Audition has many great tools for sound "restoration." I use it for similar instances, where ambient noises intrude and the audio cannot be recaptured.
Soundbooth has a surprisingly good Noise Reduction tool.
Thanks for that. I only did the beta of SB, and being the "old dog," that I am, just stuck with my Audition.
As the OP probably has SB, yours is good news.