Please come again tomorrow afternoon — I'll have more time to talk with you then.
Literal
Tomorrow [possessive-の] afternoon once more come please. That-time [topic-には] more talk-do time [subject-が] exist probably [because-から].
Two sentences joined in delivery. The second is justifying the first: ~でしょうから = 'because probably X.' Notice お話しする — the humble お~する construction applied to 話す, adding polite deference. The compound particle には in その時には (time-topic + emphasis) is the topic marker stacked on に. Natural and polite, the sort of thing a professional would say to a client.