If you cant refi my bet would be to pile up the cash in a separate account so that you can build up a nice down payment for another duplex. 

@Justin HebelkaWelcome to BP, and congratulations on making the decision to invest in your future via real estate.I have written a few blog posts that may help you get started here on BP, and with your investing.

And congratulations on the success of your purchase and sale.

Congratulations lee.

Right now, I would characterize myself in the accumulation phase, as I am essentially stock piling cash to be able to put down the down payment and have plenty left over to account for any unforeseen expenses (repairs, vacancy, etc.).My question is, where should I be keeping this cash?

@John Varner First, if those numbers are accurate, that's a solid looking deal - congratulations.

Congratulations on getting started!!

I have a 12 unit building in a small town filled with great tenants who are older and never entered the 21 st century, They deposit rent checks in a lock box in the laundry room and once a month my wife empties the box and drains a huge pile of quarters out of the coin laundry machines.

As a former tax accountant myself, I congratulate you for making the switch and joining the commercial real estate space!

Congratulations!