My advice? Find yourself a very hungry and capable lawyer and sue the pants off of them!!
There is no legal requirement for anyone to disclose that your gas lines are lacking. You are put in the position of buyer beware after you had closed. The seller has a choice of either disclosing the defiency or signing a Property Condition Disclosure Form . If your attorney failed to properly represent you then you have recourse against him. If you wish a copy of the form so you can look and see if you have seen it , my email is firstname.lastname@example.org.
Your situation willl require a licensed plumber who will be able to apply for the proper permits and install the gas lines as required. Some construction will be needed and depending on the extent you may also need other permits and lead test... Good Luck to you and contact me if you need any information... George Home Inspector
You need to speak to your attorney as soon as possible. You may even want to consult with a different attorney in case the attorney who represented you during the deal made a mistake along the way.
If I can be of further assistance, please let me know. Sorry about what happened to you, that is a very rare occurance for sure. Good luck.
Madison Estates & Properties, Inc.