。
She's behaving herself for the moment.
Literal
She [topic-は] now 's place quietly is-doing.
おとなしくする ('be quiet, behave, sit still') uses the adverbial form of the i-adjective おとなしい ('quiet, gentle, well-behaved'). It's the standard phrase parents and teachers say to active children: おとなしくしなさい. The compound する-with-adverb construction creates a temporary state of behaving in that way — different from being inherently おとなしい, which describes character. 今のところ ('for the moment') hints that the calm may be a passing phase.