Don't involve lawyers
I believe that you and I met in 2004. Knowing your denomination, the likelihood of any openly gay person having ministerial credentials restored is zero. A lawyer would have to tell you whether you could successfully sue for money, but I have serious doubts about that.
If what you really want is an apology and some sort of reconciliation with the Bishop, why not seek a non-legal meeting, perhaps with a mutually agreeable third party mediating.
Consider whether the Bishop did the "right thing," as painful as that may seem. If she is a closeted lesbian, as you say she is, she may have seen your attempt to be "ex-gay" for what it apparently was--a "phase" on the way to discovering who you really were. Perhaps she had some prejudice against you because you were "evangelical" and she is "progressive"--that would be unfortunate. Consider also that she was panicky in dealing with this issue because of her own concealed sexual identity.
I've always wanted to be a minister in the same denomination, but since the age of 20 I've been openly gay and I wouldn't have it any other way--so I've been excluded from the very beginning. I do not envy any of the clergy I know who have concealed their sexual orientation in order to remain in the ministry or even rise to the office of Bishop! That way is madness, from my perspective!
You are fortunate to be an openly-gay minister in the United Church of Christ--sometimes I regret never having shifted my allegiance to an LGBT friendly denomination where I could have entered the ordained ministry. I hope that eventually you will find more adequate employment in the UCC. Despite the UCC's alleged openness to LGBT clergy, I wonder if many aren't under-employed as you appear to be.
I think I know who this Bishop is. I don't know much about the rumors that she is lesbian, but I thought I heard she is taking early retirement due to "health concerns." Maybe she'll be more amenable to conversation and reconciliation once she is retired. I don't envy Bishops in our denomination--they are compelled to carry out the unjust laws passed by the General Conference--maybe another reason she's retiring, she can't take it anymore. How badly would the denomination treat her if she came out? Would they take away her pension? All the evidence is that she would be treated really badly.
The spiritual violence of our denomination against LGBT persons is really, really awful and getting worse. The Bishop, like you and I, is harmed by this spiritual violence. The only people who can change this are the delegates of General Conference--we need to change their hearts and minds.