So, it sounds like you could rent the entire place for $2425/month. Less all expenses (50% rule), your NOI is $1213/month. Less mortgage of $1248 leaves you in the hole $35/month. If you refi to a lower payment and don't take any cash, you could be in a better position, but its never going to be a big money maker. If you compare the $2425/month income vs. the $425,000 you think its worth, then this is a terrible deal as a rental. Buy my calculation, somone paying $425,000 would be in the hole to the tune of $1500/month
Which is not to say you couldn't find a buyer.
Was you addition of the third unit done with proper permitting and zoning approval? If not, that will cause you significant grief when you try to sell. It could end up blocking a deal, and you could end up with problems if some prospective buyer started making phone calls. If I were a potential buyer, I would certainly call both the building and planning departments and start asking questions. In a case like this (duplex converted to triplex), I ask very specific questions: " Is the property at 123 Easy Street zoned for a triplex" . " Do you have permits on file for the addition of a third unit to 123 Easy Street." If it was not properly permitted and zoned, those sort of questions might result in unwanted attention.
What are your plans and financial situation? If you sell, you have closing costs, so you won't pocket $275K. Nevertheless, you will have a nice chunk of change. You say this is an up and coming area. Effectively, you have that money invested in this property. Compare what you think you will make on this one down the road vs. what other investments you could make with that money. Its about break even, so its not costing you much to hold it. So, I think this is really just a comparison of " this investment" vs. " some other investment" .
Jon