My wife just went through something pretty similar. It is very, very difficult to find a 1-2 year masters program that will really get you into a new career and won't just be another piece of paper on your wall. Here are some things that we looked at:
Speech pathology: Most programs will take 3 years with a one year post bachelors and two year masters. Good pay (80-120k private practice). But odds are you will end up working with kids again.
Actuary: you can get into a master's program if you have had calculus. Very good pay, but a small niche industry that can be funny about hiring. Good for introverts.
Accounting/Finance: You would pretty much have to start over. Masters level courses are generally for those with an undergraduate degree in the same area.
Human Resources: Most HR people have pretty lousy jobs and make a very average salary. However, the head of HR is often a VP level position at big corporations and can be lucrative if get into a situation where you can work your way up to the top.
MBA: programs that are respectable are very, very expensive. MBAs are a dime a dozen.
Marketing/PR: I could never touch it with a ten foot pole, but marketing people get paid very well. They are everywhere. From the symphony to Walmart to the gas company to the hospital. All pay marketing/PR people good money. You may not even need a masters if you can wiggle your way into an underling job and work your way up.
Sales: Grueling and awful work. But if you are good with people and smart, you can make good money in sales without needing any further education.