Old-World Elegance Meets Modern Day life   FIRST SHOWINGS AT SUNDAY THE 14TH OPEN HOUSE 11:30 TO 1:00pm.......Step into Residence 8A at 258 Riverside Drive, where Italian Renaissance Revival architecture meets the ease of modern city life. Designed in 1908 by William L. Rouse, this storied cooperative-The Peter Stuyvesant-offers a home steeped in history yet perfectly tailored for today.  This gracious seven-room residence, currently configured as two bedrooms with a double living room, huge formal dining room, eat-in kitchen, staff room, and butler's pantry, is defined by light, air, and open views-every room looks outward, free of brick walls or interior courts. The flexible layout easily adapts to three bedrooms, offering endless possibilities.  Inside, the charm is in the details: soaring ceilings, intricate inlaid floors, original mahogany doors, and a paneled dining room crowned with carved woodwork and beams.  A decorative fireplace adds warmth, while the butler's pantry and kitchen retain their beautiful, original cabinetry-a rarity in today's market.  Life at 258 Riverside Drive blends elegance with convenience. A live-in resident manager and attentive doorman service provide peace of mind, bike room, and private storage add modern practicality. The cooperative is pet-friendly, allows 80% financing, and carries a 2% flip tax.   And then there's the neighborhood: Riverside Park stretches out just beyond your front door, 330 acres of green escape along the Hudson. Near-by is the 60,000 sq ft Whole Foods, Trader Joe's, as well as beloved local restaurants are all close at hand, with the 96th Street express stop whisking you anywhere the city leads