2009 Saturn Aura Transmission Line Replacement

Hi, I have a 2009 Saturn Aura. I recently had a 27 point inspection at the local GM dealer and was told that I have a leak in the transmission fluid, and that the transmission lines need to be replaced. Dealer quoted $475.

What part would you recommend for this? How many hours does this repair take? Approximately what should I expect to pay?

Thanks,
Dave