The gang extorted a huge sum from the wealthy man.
Literal
Gang [topic-は] that rich-person [from-から] enormous money [object-を] extort-took.
ゆすり取る ('to extort') is a compound verb: ゆする ('to shake [down]') + 取る ('to take'). 莫大 ('enormous, vast') is a formal na-adjective for huge amounts. 金持ち ('rich person') is a compact descriptive compound.