The 5,725-square-foot penthouse at Morton Square that Ashley Olsen bought and renovated with her twin, Mary-Kate, years ago just went on the market for a little under $12 million, but that’s not the only real-estate property that she’s letting go. A source says that Lance Armstrong’s reported inamorata has just vacated the three-bedroom duplex on Grove Street she’d been renting since November 2005, around the time she and her sister left NYU and took separate apartments. It’s a far cry from the spanking-new condo the two just sold: Though it’s thoroughly updated, the West Village place is decidedly old- world, with original woodwork and pocket doors. It’s on the market for $15,000 a month through Corcoran’s Tatiana Cames.