Cap rate for small town? Less then 5,000 population.

[Doug Bloes]

I just tied up my first apartment building in a nice small town. It has 8 units and the inspection came back in great shape. Its the best in town! Owner is retiring. Rents are $100/unit less then the market rate. Expenses are extremely low and the tenant base is great. Would like to increase rents over the next 2 years to market rate and allow pets to also increase income. I'd like to then refinance and pull the increased equity out. How do I know what cap rate to use when determining the value? I purchased the property at $330,000, NOI is $37,000. That means I bought it at 11%. Is that the same cap rate I use when I calculate my future refinance? Am I missing something? Any help is appreciated, thanks!