Welcome to the forum. You will no doubt want a package that can handle files from architects and surveyors,so autocad is a good start. autocad LT would be fine to start with but there are many features in the full blown version that is not supported in the LT version. Mainly the LISP routines and customisable menus and commands.
You will also want a nice program like coreldraw or illustrator to dress up your presentation drawings.
A great person to PM is F7,his background and knowledge would come handy to a person like you. hes right up on the presentation skills too.