Help! New RE investor - Is this a good commercial deal?

[Lauren Acrich]

$4 million for 54 unit mobile home park at a 6.45% cap rate, anticipated to increase to a 7.04% cap rate within the next year. 

NOI: $257,000

Current Loan: 2,600,000 at 4.90% principal & interest amortized over 30 years. 

If I were to put down $100,000 and finance the rest of the 35% down payment = $1,300,000

How would I calculate this profit? 

Any and all help is MUCH appreciated!!