Improve Exiting Windows Desktop & Android App

I need someone experienced with .NET & Java to improve our desktop app (windows) & Android app, this is a chat application. The apps are build already but it has some problems, you would get assistance from our previous developer, who would be there to help you all along. The is approximately of 7 working days or less for a decent coder. You must be able to communicate through skype & phone calls every day, if you are not okay with it please dont apply. We would provide the new design teplate as well. If you have any questions please free free to ask & put "Chat" before your application/bid so I know you read the description, anyone not doing it would be tagged as spam bidder.