It's bit unusual to get a request from the US. I try to do my best to help you.
Indeed there are possibilities to convert your TX to 2.4 GHz. One way ist to get hold of a HFMx Modul and a suitable receiver as shown here:
There are few disadvantages:
1. It is no longer in produktion, so you can only get it on ebay e. g.
2. It is an external solution, that means it is attached to your TX from from outside linked up via a lead to the multifunction socket
3. You are bound to the MULTIPLEX-M-LINK-systm (but that is also due to other systems!)
What you might be looking for is an internal solution where you add a 2.4 modul inside the TX. This is possible with many systems: M-LINK, jeti duplex, (the expensive ones) and others from Asia as for example Assan, Frysky and others.
What you need is some skills with soldering and some basic knowledge on electronics.
There is a video on YouTube (look for: Multiplex Cockpit MM Conversion to 2.4Ghz). The video is in English and might be a great help for you. It shows the instalation of a Hobby King system: FrSky V8HT 2.4Ghz DIY-Modul.
As I said before almost any other 2.4 GHz system that works with a PPM input can do the job.