You would need an 11 wide or an 11 1/2 medium..good luck! :-)
If I Wear A Size 9 1/2 In Men's Shoes What Will My Shoe Size Be In Womens?
Most likely a size 11 or 12, though if you can find them a 11.5 should fit perfectly but they are hard to find in womens shoes.
Well I wear a size 8 in mens shoes, and a 10 in women's, so maybe a 10 1/2 or an 11 depends on who's making the shoe