I'm sorry, you still didn't ask a question. I know you're upset and a little worried and I'm here to assist you, but this works better if you ask a specific question. I'll go ahead and provide some information that may assist but if you have specific questions please ask.
First, to find a lawyer go to www.lawyers.com and in the section for Area of Practice enter "Civil Litigation". You'll find a lawyer there that can assist.
There is no need to try and contact Sears CEO, you'll never get an answer back. You can ask for Sears "Claims" department and they will usually tell you how to file a claim with them.
I have read your insurance policy and it does not provide protection for this incident. If you look on p. 7, paragraph 13, that states it won't cover damages when the loss is due to water escaping from an appliance. Also, on p 5 Coverage A it states that this policy only covers your residence.
So, what you need to do is find a lawyer to represent you, they will contact Sears and turn in a claim and then may try to make a claim under the insurance policy as well if they spot any loopholes. If the other owner sues you then they will defend you and attempt to place the blame on Sears (which shouldn't be hard) by adding them in as a cross claim.
Please ask any follow ups in this thread.