Hi! Hang in there--you will get through this decision!
My daughter is almost in high school, but I remember the tough educational decisions we had to make at this early stage, too. One of the most frustrating things is when you cannot find the resources that you feel that your child needs. I am going through the same thing even at this stage. For us, it means moving to a new place--but I know that is not an option for many people. In our current area, there was only TC--oral ed was not an option(during my daughter's elementary years). She was very oral(had attended an oral preschool) and the decision was made to let her mainstream and continue AV therapy. It worked out okay until she hit adolescence--then the social issues came into play.
Since your options are also limited, it will be a tough decision. It just isn't fair that parents of deaf children don't have ALL options available to choose from when making these decisions! Try to picture your daughter in each situation: the bi-bi school does not seem to be meeting her oral language needs and may not improve much in the future, the mainstream choice may be very tough if she will be one of the only children who do not speak in school(can be done though), and the oral program MAY have issues with ASL. However, if this oral program is through a public school, I would think that you would have every right to get her in that program WITH an ASL interpreter. You could probably do the same thing in a mainstream situation, but think of the social issues--if there are other deaf children in the oral program, that is definitely a plus. I only WISH that my daughter had that option in her public elementary school! The one thing she missed out on that REALLY seems to matter to her: knowing other deaf children who are like her.
OK--so picture each situation: if she continues in the bi-bi school she will have deaf friends but her oral language will not be encouraged(according to what you have said)--and it seems that you are no longer happy there(once again, just going on what you have said)--are there other kids with CIs there?--if so, then have you talked to the other parents about the speech issue at the school? One important thing if she stayed there--wouldn't she really really want to have friends who are "like her"(deaf with CIs)? If there are, then that is good--hopefully you and the other parents could "force" the school to meet the needs of your kids with CIs. If your daughter is the only child with CIs, she may end up feeling "all alone." The same goes for the mainstream option--she could do that and have an ASL interpreter, but there won't be a lot of AV therapy going on--if she felt that she "fit in" with the hearing kids it could work, but if she feels "all alone" then it will be tough--not impossible, but tough. With the oral ed option--hopefully one in which you COULD absolutely get her an ASL interpreter--she would probably have deaf friends who wear hearing aids and CIs. At this age, there will be a wide range of "oral ability" among the class--some of the kids may speak wonderfully and some may have very little oral language--for the most part, they will probably all feel "the same" because they are all deaf and have "things on their ears"(something most hearing kids do not have). It would be SO wonderful if your daughter could make a friend "like her" at this age!! A little girl who is fluent in ASL, has CIs, and is learning to speak--if that is at all a possibility, I would go for it. If there was some way to go back for my daughter, I would try to find her a friend "just like her" from kindergarten on--and hopefully they could go all through elementary school together and have a lot in common through the years. I know it isn't always possible--sometimes there just aren't any other deaf kids the same age as your child--but if there is, I would jump at the chance to make that connection.
So, I guess the main thing is: where would your daughter be the happiest and make the most progress? She definitely needs the ASL right now--don't let them take that away from her wherever she goes. And, it sounds as if she would do great with AVT--and hopefully she can continue that plus get a lot of oral language instruction and exposure at school. And the social issue is SO SO important: if you could find even one little girl her age going through the same thing, that would be so great for her. So, if you can find all of that at the bi-bi school, that is great. If you can find it at the oral program, that is great, too. You may be able to get it in the mainstream, but it is harder to find deaf kids in that situation. Good luck in whatever you do! I am sure she will be happy in the right situation. Good luck!