Hello
I am an OS X and iOS developer. I have been working with these platforms for over 7 years, building stand-alone and client server applications (an iOS app that interacts with a server app using RESTful APIs, that I also created). In fact I have been using client-server REST communication for autoupdate mechanism implementation, for uploading data onto cloud services, downloading news.
One of the applications for iPhone that I build was a forex application that consisted of a server app (that provided forex data to client apps) and a client iOS app.
I have worked with ruby on rails. Was the choice of RnR made because you already have a partially finished server part?
I do believe I have nice UI design skills, and I am attentive to details.
The budget specified in a bid is only based on the proposed by you duration, as I do not know any specific about the app.
I would be happy to help you with the project!