Piano and Voice Music Transposition

I need sheet music originally written for piano and voice transposed to a different key for performance purposes. The song is Back to Before from the musical Ragtime. I have the sheet music available in various keys (from music notes), but not in A flat major (which is the key I'd like to have it in).

Ideal skills and experience:
- Proficiency in music theory
- Experience with sheet music transposition
- Familiarity with piano and vocal arrangements
- Attention to detail to ensure accuracy