Commercial (12 Unit) Cash Out Refinance Help

[Johnny Hastings]

I've been digging on this for a little while, and can't find anything concrete on where to start. 

I have a 12 unit that I bought in a medium state of distress in 2013 that I've since turned around. The place is running very well now, and I've done tens of thousands of dollars worth of capital improvements to improve the outside, the parking lot, the individual units, and the heating infrastructure. 

I paid $420K, and I've had investors come along and offer $625K for it; despite the fact that it isn't even on the market. If I math put it into my valuation spreadsheet, at a cost $792,500 with current incomes: the cap rate is at an 8, and it cash flows $800 per month if a person were to put 20% down and get a 4.5% rate at a 20 year amortization. So there's definitely definitely some room to work with here, considering I owe around $290K.

My question then, is: How do I go about doing a cash out refinance on this?

Should I take it to my local bank that currently has it financed, and see what they'll do for me? 

Should I shop it around to other local banks? 

Is this something I need to seek a mortgage broker on? 

How and where would you start trying to get this done?

Any and all advice is appreciated.