I would tell this client that you are sorry to have wasted his time and that you can’t go any cheaper. This client will either go ahead with the job at the price you quoted (which is higher because it is now a 2 camera shoot instead of one, plus all the extra post that this will require) or he will disappear. If he disappears, you probably would not have wanted to work with him anyway. If he is so red hot to do business with you, what happened to the multiple shows that he wanted last January.
I have found that if you back down on the money thing the job never goes smoothly. The client expects to have full work for the price they have paid as negotiated and you will go into this job feeling like you cut a deat and that can’t be good for your attitude. It has been a difficult thing for me to turn down or even lose a client because of this, but you will find that the clients you do get will respect your work and feel it is worth the money that they paid. Also, your prices are quite cheap for what they are asking you to do.