Welcome to the PICAXE forum.
When you say you are "desperate", how much of the project have you attempted or completed, how far have you got, what works, what are you up against the wall with, and what previous PICAXE, electronics and robot vehicle experience do you have ?
There is quite a lot to that project but it can all be broken down into smaller parts, all of which can be managed individually and brought together as a whole.
How urgent is your requirement ? Is it a school project or coursework ?