DCC, how to do it and other questions?

[Clueless]

I am wondering I currently have 3 trains that are all Analogue but I am toying with idea of going digital but dont trust myself with a soldering iron. Are there any shops that will fit Decoders for the right price and would it be covered by Hornbys warranty

or would i send it to hornby to get it done?

The trains I have are:
Smokey Jow (0-4-0)
Thomas the Tank Engine (0-6-0)
Toy Story 3 western Train

And my father has a vast arrangement of trains he has promised to give me that I will come

back to when I get them.

Which decoders would I use for the trains I currently have and what would the cost be roughly?

I am wondering is Digital the way forward?

Would I need new track or would a digiatal contoller be sufficient to

run the engines?

If I do have a controller programme it then turn it off at the mains would it reset to factory settings?

any help please guys as I am totally confused