Not very far. Go through the mall towards Admiralty MTR, but on the upper level. Enter the elevated walkway across Queen's Road (by the restaurant area in the mall) into the Queensway mall. Turn left in the mall, walk all the way through the two buildings and into the elevated walkway between the Bank of America tower and Fairmont House (Fairmont House on the left, BofA on the right). Make a right towards Hutchinson House and go to street level right by the Alain Figaret store. On your right you'll pass the AIG Tower, the RC, and the HK Club. Straight ahead across the Cenotaph is the MO. You should be able to see it as soon as you come to the end of the elevated walkway.

In total, probably no more than 15 minutes walk.