You can get a trainer in any form: Kit, ARF, or RTF. Since you already have a transmitter I recommend an ARF to get started. After a while, if you want to build a kit, you can decide which one you like and start the project.

You can buy or make an interface to connect your transmitter to the computer. I thought I had a link but cannot find it.

Found a link for the interface: http://www.clonepac.freeserve.co.uk/products.htm