。
She'll probably get better in a week or so.
Literal
She [topic-は] one-week even-if-pass [if-ば] become-better will-probably.
一週間もすれば is a soft estimate — も here is the 'as little/much as' particle (similar to 一万円もあれば '500 dollars or so will do it'), and すれば is the conditional of する acting as the conditional of 過ぎる ('pass'). The construction reads 'in a week or so / give it about a week.' よくなる ('become better') uses the い-adjective adverbial pattern いい→よく + なる, where いい/よい is irregular (the よく form is the standard adverbial root). ~でしょう softens to a probability claim, fitting medical or recovery contexts where the speaker can't be certain.