See another lawyer for possible malpractice proceedings against this lawyer. In a legal malpractice case, you have prove a trial within a trial, i.e., that the case your lawyer mishandled would have been won but for his negligence.
Disclaimer: I'm only licensed in CA. Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.