Comedy voices - I can see the funny side of that!

Getting rid of the intermod is a lot of work. I have done it many times in ProTools with varied results.

You could try Cedar Audio - CEDAR Audio Ltd: Audio Restoration Systems

email them a sample and see what is possible - shouldn't be too expensive because the process is fairly automated - unlike a protools dubber who will spend hours cutting/filtering etc etc. I am always amazed at what they can achieve.

If you are OK with editing sound I'm with NikoSony - go and re-record the dialogue you need in the church or similar (acoustically) location with the same camera/mic and position.
Look up 'dialogue looping' on the net and employ this technique if possible. Basically you play the original dialogue to the person and then immediately record them repeating it. Keep it in small chunks if possible and then cut together. You will be amazed at the results.

Good luck!

'Film making is very often about saving yourself from disaster' - You are doing something wrong then.