。
She works exceptionally well at my office.
Literal
She [topic-は] my office [at-で] outstandingly well works.
飛び抜けて is the te-form of 飛び抜ける, a compound verb literally meaning 'to leap and pass through' — used adverbially, it conveys 'standing head and shoulders above,' 'exceptionally,' 'by a wide margin.' Common collocates include 飛び抜けて速い (exceptionally fast), 飛び抜けて優秀 (outstandingly excellent). The で here marks the office as the location of the action (work happens there), not a means or instrument. 良く働く is a fixed-feeling collocation meaning 'works hard / works well' — Japanese praise for diligence.