refinancing a rehab for rental

[Tom Murphy]

I originally purchased a 3/1 ranch (1,400 sqft) for $45,000.  We will have improved literally everything with a rehab investment of $80,000.  We have a purchase rehab loan presently.  While our original intent was to flip this home, I'm listening to Brandon Turner's audio book Rental Property Investing and thinking this could be a rental.

With this in mind, how do I calculate the loan for the rehabbed house? Do I just put the original pp of $45,000 in the rental calculator then add the rehab costs, other costs and ARV or do I look at a different loan amount since I've rehabbed the house and will refinance? If I use the former, my cash flow is $350 based on area rents. But, if I figure a different loan amount, considering the refinance and rehab built in or ARV then the numbers look different.

Thanks,