need help re: auto lease

Ok, I have been asked to assist in getting a new car for my office (lease due to tax reasons). I don’t really drive, so my knowledge of anything car related is pretty much non existant.
Can anyone help me with regards to what sort of information I should be having/searching for?
The boss wants to trade in the current lease she has (doesn’t want to use the same dealership apparently), and has said she has a preference for corrolas.
Other than that, what should I look for to get the best possible deal, in terms of best car/best rates etc?