Living with someone post breakup

[SVTHORD]

So I just got back from AC and she tells me that she decided to leave as soon as classes were over (2 weeks) and we need to discuss tomorrow how we're splitting things up.

Given that I know she can't afford to pay me outright for whatever she takes in the split is some sort of payment plan my best option? From watching enough judge shows I would think a contract would be a must.