Oh wow...that is just awful. I agree to check with the realtor about the "move-in" condition part of the contract. That is obviously not move-in condition and you should be reimbursed for getting it to that point.
Remember to start at the top and work down, so if you are going to be ripping out ceilings, then start with that. Pest elminiation is going to be one of the first things you are going to want to do as well. Carpets and flooring are last and you might have to do them a couple of times. The last one maybe after the movers are done.
You got good advice on where to find an industrial cleaner. Other key words to help you are: commercial cleaners, disaster cleaners, and crime scene cleaners. You also got good advice about getting a firm quote from them. You are not going to be able to finish this on your own, so keep looking until you find them.
Movers are expensive. Providing your own boxes will save you a ton. Look on Craigslist for someone that just moved and has used boxes available. I used emove.com when I moved and had very good luck and it was much, much cheaper than the usual companies. You can hire someone to come help you pack and another group of muscly young men to load everything into the truck for you and then unload it. 4 hours with 3 college age men on summer break to load my packed boxes efficiently onto the truck cost me $250. Money well, well, well spent.
Maybe if you have some people over cleaning the house, you could start on packing some of the more intensive stuff to save a little money and time there. but if your hands feel like they do, that is going to be hard.
Hope you are feeling better soon and back up to your full capacity.

If you SIL fusses at you, just tell him its his Mother's Day present to you to not have to scrub anything any more. That should work.
