Your problem is that you have a Chevy that is stranded at a Ferrari dealership. I think you need to make a few phone calls to Schellville airport and Sonoma airport, which are within 20 or 30 miles of Napa. Somebody at one of those two airports will be able to help you. Removing the wings, flat-bedding it over to Schellville, installing a cylinder, and reinstalling the wings should still cost you less than $4000.
I'd have to agree with others here and say that getting it onto the right airport is the first priority. Because the ESTIMATE from the Jet place can change once they find a pebble embedded in your upholstery, etc. There are several far more experienced mechanics on this forum, and they can all feel free to correct me, but having a Part 61 airplane annualled and repaired by a 135 or 121 maintenance facility does not strike me as a cost-effective option.
With all due respects to the professionals at most jet centers, BTW. They are very highly trained and talented people, and are focused on safety, and focused on doing a good job. It's just that their normal methods and practices are oriented for a different mission, under a different set of rules, than most small GA shops.