Completion of an existing incomplete Sencha Touch native mobile application

We are looking for a developer to complete a native application which a previous developer was unable to complete. The mobile application is based on an existing web application called Rolio ([login to view URL]). The application has been developed using Sencha Touch, so the prospective developer MUST BE HIGHLY EXPERIENCED in Sencha so that they can pick up the codebase and complete the application. The Sencha Touch application must integrate with the PhoneGap framework to produce native apps, that can be distributed on Apple iOS & Android devices. The App communicates with JSON-P compliant web service which provides most of the data required to drive the application. Application also integrates with Facebook and Twitter APIs for remaining data. 95% of this service integration work has already been completed but the developer must be able to complete the remaining work as well as fix any outstanding bugs. Developer must have strong UI skill-set including CSS/SASS, and especially Javascript. Please only submit bids if you have previous suitable experience and have a portfolio of existing applications which I can review to see the quality of your work. Please also ensure you check out [login to view URL] and sign up in order to understand the requirements of this project and only submit if you are 100% confident you would be able to complete this project successfully. Based on analysis of the existing code, around 80-90% of the project is complete with the PhoneGap integration remaining. The anticipated time frame for this work is around 3 weeks. Firstly, I shall review your bids and check your feedback and existing portfolio. The shortlisted developers will then receive full documentation of what is required so an accurate quote can be given and a Skype meeting will be arranged to discuss the requirements in detail. There will be much more development opportunities for the developer if they are able to complete this job successfully.