I'm not sure how helpful this answer is for your current application, but it may prove helpful for the next applications that you will be developing.
As iOS does not use Java like Android, your options are quite limited:
1) if your application is written mostly in C/C++ using JNI, you can write a wrapper and interface it with the iOS (i.e. provide callbacks from iOS to your JNI written function). There may be frameworks out there that help you do this easier, but there's still the problem of integrating the application and adapting it to the framework (and of course the fact that the application has to be written in C/C++).
2) rewrite it for iOS. I don't know whether there are any good companies that do this for you. Also, due to the variety of applications that can be written which can use different services and API, there may not be any software that can port it for you (I guess this kind of software is like a gold mine heh) or do a very good job at that.
3) I think that there are Java->C/C++ converters, but there won't help you at all when it comes to API differences. Also, you may find yourself struggling more to get the converted code working on any of the platforms rather than rewriting your application from scratch for iOS.
The problem depends quite a bit on the services and APIs your application is using. I haven't really look this up, but there may be some APIs that provide certain functionality in Android that iOS doesn't provide.
Using C/C++ and natively compiling it for the desired platform looks like the way to go for Android-iOS-Win7Mobile cross-platform development. This gets you somewhat of an application core/kernel which you can use to do the actual application logic.
As for the OS specific parts (APIs) that your application is using, you'll have to set up communication interfaces between them and your application's core.
