The Omega Arsenal was located in the Time Vaults on Gallifrey, (TV: The Day of the Doctor) beneath the Capitol. (PROSE: The Day of the Doctor, A Brief History of Time Lords)
The Moment was kept in the deepest time vault, Time Vault Zero, for billions of years. It was recovered, on the final day of the Last Great Time War, by the War Doctor. (PROSE: The Day of the Doctor)