Here’s what’s waiting for Yankee GM Brian Cashman in Manhattan Supreme Court early next year: his tanned, rested and ready-for-battle accused shake-down mistress, Louise Neathway.

He’ll be the star prosecution witness at Neathway’s extortion trial — which a judge yesterday said will start in early 2013.

The blond Brit came to court yesterday in a silky fuschia blouse and wide-leg white pants.

She’s accused of shaking down Cashman for $6,000 by threatening to expose their 2011 affair to his then-wife and the media.