...Would you pay the fines now or let the responsibility fall on the CPA?...
Hahaha... sorry to laugh at your misery, but it is hard to believe there still is so much naiveté when it comes to matters of taxes. With the caveat that I am not a lawyer, I suggest you pay the fines, like, right now, even before responding to me on this thread (to stop the accumulation of penalties and interest). Taxes are YOUR and solely your responsibility, regardless of who prepared the return. Just ask guys, including celebrities, who sit in jail, blaming their CPAs. You can then pursue a separate legal or licencing-related action against the CPA.
paying the full amount, I would then go visit the IRS, in person, without a lawyer, and kindly ask them to consider waiving the 3x penalty, explaining the situation, that it was not intentional, etc. I have no idea whether that would actually work, but that's what I
would try if in your shoes. You have nothing to lose.
EDIT 2: As for finding a lawyer, I do not think he would help with the IRS, as it is a rather clear-cut case from the IRS point of view. At the same time, even if he would miraculously manage to fully eliminate your fines, most lawyers these days would not even look into anything without about $3,000 in their pocket first. The same goes for pursuing civil action against the CPA. You might want to look into small-claims court though.