Hi !
I am an experienced iOS App Developer.
Its sad that your previous developer left the project half way.
I won't do that if i am finally hired.
Secondly, i would require further details regarding the project.
And,
Only Xcode should be used for iOS app development, i can try and myself port your current app to Xcode - Objective-C.
Message me and let's get to work as soon as possible.
Thanks,