Sorry for the delayed response - been in Hozzy for some tests on me ticker.
All the info you need to lay a york stone driveway is on the
Stone Paving page.
Basically, you need to excavate, install a sub-base and then lay the chosen paving. As you won't be doing the work yourself, it's probably easiest to invite 3 or 4 contractors around to take a look and see what they have to say.
Cost depends on so many factors, not least of which is the type of paving. If you go for York Stone again, it could well cost 100-120 quid per square metre to supply and install, whereas block paving might only knock you back 60-70 quid poer square metre. Then you have to consider any drainage that's required, accommodation works, access problems...best to call in a few local contractors and get them to price it up.
In the meantime, you should decide on what type of paving you prefer. Do you want Yorks again, or summat more modern, like block paving or resin bonded aggs? Maybe PIC or even tarmac - there's loads of choice, but only you can make that decision, as it's you that has to live with it, not me!
Did you have anything specific in mind?