Thank you for your replies. Car is going to the dealer next week, they want to try to recharge and desulfate the battery and test it prior to changing it out.
And with the current USD/CHF exchange rate, it is only about USD 450 for the replacement battery.
Will post back with results.
AndrewC, I do mention investment for a battery tender because it is 100 USD at least for a quality tender plus another 50 for one of those stupid cable spool. I live in a condo and my car is parked in the underground garage.