question? Thinking caps on!

[Samuel Everett]

Hello everyone,
I have come across a quadplex (2 for $550 and 2 renting for $650. all units rented with 8 months or more left on lease) been there, in excellent condition inside and out. good tenants. seller asked for $305 but the inside scoop is she will accept $250,000 in cash for a quick close. My ole credit score , she aint what she used to be (630 to be exact) How can an ambitious slug like me give her $250,000 cash and a quick close? I need you fella's expertise and fast on this one.