。
She had something to talk about with him.
Literal
She [topic-は] he [with-と] talk [subject-が] existed.
話がある is a set phrase: literally 'a talk exists,' used to say 'I have something to discuss.' Often a setup for a serious conversation. The particle と marks the conversational partner. Note が — not を — marks 話, since 話がある uses the subject-が pattern of ある ('to exist').