I hate to tell you this,but I think you answered your own question. That sounds like a HUGE issue for ALL of the townhome owners, so I would definitely approach/press the HOA Board. You might also obtain 2-3 quotes for individual coverage, have those available to prospective buyers, and then offer to pre-pay a policy for a year (similar to a home warranty plan). And, if you've not already done so, I would recommend discussing the problem with your Realtor and seeing if you can't come up with some alternative solutions.
Best of luck!