Buying First property with sellar financing

[Jarrett Ware]

I'm trying to purchase my first house it is a 4 unit property for $330,000 and I am currently renting one of the units. It is a 4 unit property one 3 bedroom unit, two 1 bedroom units, and one 2 bedroom unit. All the units are currently rented but they are under rented for the area. The property is bringing in $2800 a month in rent. The owner is willing to sell the property to me for 10% ($33,000)down and then a mortgage of $1200 a month for 7 years then I will have to buy the property out right. The house is old but taken care of, everything works and looks good. The issue I am having is that I don't have great credit and I can't get approved for a personal loan or a conventional mortgage. How could I go about funding this deal.