Mobile CSS and JS fix needed

I have a small little app built in jquery mobile that we're using to display a web app for android and iphone users. The problem I'm running into is that some older devices display the css/html really badly and some do not pick up the mobile side at all. The site is built in Wordpress but is built using a responsive theme. What I need is someone who can come in over the weekend and just hammer out some code and fix this problem and getting this small little app working across all android, iphone and ipad users to a point it is acceptable. Acceptable meaning that it displays mostly right and the JS and menus all work correctly as well. Our in-house developer has attempted to fix this but we are having other issues that must be addressed in other areas right now. Please don't PM me a canned response, it will be removed without consideration. If you are experienced and actually reading this, then respond with the domain name of the site so you can test the page yourself, as well as a gameplan for how you intend to fix this, the time involved and when you can start. I am looking for someone to fix this over the weekend as it is a very tiny job. If you can do this please do not bid. Thanks!