Absolutely. The 800m is primarily an aerobic endeavor, so it is important that you are fit. I'm not sure how much you're running presently, but your goal should be to improve your aerobic fitness: that means easy running at conversational pace, and an occasional harder run of ~20 minutes in duration.

That said, in such a short event, a fair deal of power is required. Thus, doing short hill sprints (from 60-200m) in the months prior to your attempt would be helpful. Be careful to introduce these slowly. Start with only two, and work up to, say, eight over a period of as many weeks.

Finally, interval work is crucial, although one has to be very careful -- too much too soon, and injury is basically guaranteed. Focus on workouts with rest time greater than or equal to your work, like 4-5x400m or 6x200m. You could do one workout a week.

My favorite book is Healthy Intelligent Training by Keith Livingstone. It's an incredible resource. Also, there's a ton of theory on 800m training in the following thread

http://www.letsrun.com/forum/flat_read.php?thread=2669719

Lastly (and most importantly!), get a coach. Good luck to you.