Looking at Duplex but is this a good move?

[Mary Ann]

I need to move out of my apartment by November.  It's a problem that gives me room to do my first investment.  I found a duplex that is FULLY rented now, top and bottom floor.  Owner is willing to sell contingent on top floor being vacant beause I want the top floor, and tenant lease is almost up.  I am paying $1400/mo rent now and could be paying a mortgage.  Though, it is a small place, I'd have to sell my furniture (more cash, hello!), it will give me the rent from downstairs to pay the mortgage.  The rent is about $650/per apt, house asking is $135000.  My concerns:  1) should I leave both tenants in there, and find another place of my own? or 2) should I take the upstairs, and if I do, what are some things to consider?  

Im not prepared for both apts to be vacated since I just started a new job, have nontraditional income, and need that security.  The seller wont do seller financing, so if I want this, I have to be very CREATIVE, find a no/little money down option, or other financing.

The duplex is small, in a single family home area, total house sq footage is about 1050.  However, it is just 2 miles from the beach, great vacation rental potential down the line.  

Any thoughts appreciated! Thank you!