you will need a lot more than a few hours of playing with a flash to do something useful with it. if you haven't used a flash before, and you're in a hurry, ditch the flash idea for now, use continuous light instead if you can (even window light will be easier to master than full flash lighting, you can use the onboard for minor fill flash purposes). auto mode is not what will help you here, understanding light is what you will need first. (so, i guess, my point is: the answer to your question is "no."
). if you do buy a flash, take your time chosing it, play a lot with it, read a lot (you can start with the strobist website), and have fun, but don't expect nice results on auto at first encounter.
(notice how i don't even go into a discussion about diffusers and so on. i didn't miss the question...
)
hope this helps