Looks like you have a great Verbal score. Yet, I would take the GMAT again to bring your Quant score up. If you have spent 4 years in accounting, you can handle the math - you probably just need to learn some of the tricks. Having over a 700 will increase your chances by a ton. Look into test prep books and websites.
You also need to write more than a good essay, you need to write a REALLY AMAZING one! Once you score over 700, start writing and re-writing and re-writing. Campus visits and informational interviews with current student, alumni, and admission staff are also a very good idea.
ballpark chances right now: maybe less than 25% ~ but don't think of applying to B-School in term of chances, you need to do a lot of research to determine which schools would be best for you, and give them your best. I'm sure you can get in with a 680, but over 700 will show schools you are interested, and then blow them away with an amazing essay.
Hopes this helps & good luck!