How to get my Android app ported to iPhone?

My partner and I have a webapp with a pretty good Android client. Problem is, we're Java developers and don't really do the Objective-C stuff. I know most of the iPhone development $$$ is spent on things like design, art, etc, but we've got all that. Does anyone know of a lower-cost solution that can basically duplicate our work, re-using the same URLs/JSON APIs for the app, just on the iPhone platform?