jigeumeun kapeeseo joyonghi iyagihago isseoyo.

지금 means now. -은/는 is the topic marker, so 지금은 means as for now / right now (speaking of now).
It sets a “time topic,” often implying contrast with other times (e.g., before/usually vs now), even if that contrast isn’t stated.

-에서 marks the place where an action happens (the “action location”). Since 이야기하고 있어요 (talking) is an action, 카페에서 is natural: talking in/at a café.
-에 often marks a destination (to) or a location of existence (있다/없다) rather than the place where an activity is performed.

Yes. Korean often omits the subject when it’s obvious from context. You could say:

• 저는 지금은 카페에서 조용히 이야기하고 있어요. (I’m talking quietly at a café now.)
• 우리는 지금 카페에서 조용히 이야기하고 있어요. (We’re talking quietly at a café now.)

Omitting it sounds natural in conversation, especially when you’re already talking about yourself/your group.

-고 있어요 expresses an action in progress: be doing.
So 이야기하고 있어요 = (someone is) talking / having a conversation (right now).

It’s the common spoken polite form; in writing you might also see -고 있습니다 (more formal).

It’s not strictly necessary. -고 있어요 often already suggests “currently,” but 지금(은) makes the “now” explicit and can add contrast/emphasis. Compare:

• 카페에서 조용히 이야기하고 있어요. (We’re talking quietly at a café.)
• 지금은 카페에서 조용히 이야기하고 있어요. (Right now, we’re talking quietly at a café.)

조용히 is an adverb meaning quietly, and it modifies the verb phrase 이야기하고 있어요.
Common positions are flexible:

• 지금은 카페에서 조용히 이야기하고 있어요. (very natural)
• 지금은 조용히 카페에서 이야기하고 있어요. (possible, slightly different focus)
• 조용히 지금은 카페에서 이야기하고 있어요. (possible, more emphasis on quietly)

이야기하다 commonly means to have a conversation / to talk (with someone) and feels interactive.
말하다 is more like to say / to speak (words) and can focus more on delivering a statement.
In a café situation where two or more people are conversing, 이야기하고 있어요 is especially natural.

-어요/-아요 is the standard polite informal style (very common in everyday conversation).
Alternatives:

• Casual (to close friends): 이야기하고 있어.
• Formal polite: 이야기하고 있습니다.

Time words like 지금, 오늘, 내일 usually don’t take location particles like -에서.
지금에 is uncommon in this meaning. Instead, Korean uses:

• 지금 / 지금은 (now / as for now)
• 지금부터 (from now)
• 지금까지 (until now / up to now)

Korean typically follows (topic/time) + (place) + (manner) + verb.
Here:

• Time/topic: 지금은
• Place: 카페에서
• Manner: 조용히
• Verb: 이야기하고 있어요

The sentence is built around the final verb; the earlier parts add context (when/where/how).