。
She had to make her own clothes herself.
Literal
She [topic-は] [by-herself-自分で] clothes [object-を] tailor-up-finish [must-なければならなかった].
仕立て上げる (仕立てる + 上げる) is a compound verb meaning 'to tailor (clothes) and finish, to make to completion.' The 上げる suffix marks 'bringing to completion' — a productive aspectual modifier. ~なければならない is the obligation pattern; the past ~なければならなかった makes it a past obligation. The phrasing implies necessity rather than choice — perhaps poverty, scarcity, or a context where ready-made clothing wasn't available.