UPDATE 1-DiamondRock to buy hotel in Times Square

* Purchase price of $112.5-$135 mln

* Sees deal at $178 mln if number of rooms increased

* Says purchase price depends on final number of guest rooms

Jan 18 (Reuters) - Lodging-focused real estate investment trust DiamondRock Hospitality Co (DRH.N) said it would acquire a hotel property under development in Times Square, New York City for $112.5-$135 million.

Upon completion, the hotel is expected to contain about 250 to 300 guest rooms.

The number of guestrooms could be increased to about 400, if certain permits are obtained, which could push up the purchase price to about $178 million, the company said in a statement.

The hotel, which is being developed by an affiliate of Walton Street Capital LLC and private real estate investment company Highgate Holdings, is expected to be complete in about 24-30 months, with an anticipated opening date in 2013.

Highgate Hotels is expected to operate the hotel upon completion.

Shares of the Bethesda, Maryland-based company closed at $12.54 on Tuesday on the New York Stock Exchange. (Reporting by Renju Jose in Bangalore; Editing by Jarshad Kakkrakandy)