Thank you for your question.
You have a very tough case in front of you if you choose to proceed. First of all, a warranty will exclude the payment of lost profits in this situation. That would mean that you would have to prove a negligence case. This would require that you hire an expert witness to provide testimony that the original inframing was done in a negligent manner and that the repairs which failed were also done in a negligent manner. If you prove this, you may then become entitled to recover your lost net profits.
If you consider that you may have to hire an attorney by the hour (or through contingency) and may also have to pay for the expert witness, this could greatly reduce the amount you could potentially recover from this. An hourly attorney may charge you around $20,000.00 or more to take a case to trial. A contingency attorney will charge 35-45% of your winnings, plus expenses. The expenses in this case for the expert witness may be $5,000-$10,000. I say this because you should consider whether it is really economical to pursue litigation, as you stand to have what you get back significantly reduced by the costs (assuming you win).
The correct venue for the case is Pittsburgh. If you search www.martindale.com you will find a list of good attorneys who may help you on this case. We cannot directly refer you to an attorney as it is prohibited by the website.
Please let me know if you have further questions regarding this matter. Please also remember that I do not get paid until you rate my answer positively. My goal here is to give you an honest answer, which sometimes means that it's not the answer that makes you happy. I appreciate your business.