Most people that have cars last that long and have blown engines or transmissions tend to get them replaced. I don't know how much an engine or tranny would cost to replace, but replacing the battery in a car that has given you that many miles seems like it might save you money in the long term. Do you know how long it would take in gas savings to make up the $6000 or so for the new battery? It might be a factor.

Have you taken the car to another dealer for a second opinion?

If it were me and the car was in otherwise good shape I would just fix it up for another 150K miles.

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"