They are sold in Department stores like Macy's and Lord and Taylor. They also have individual stores where you can buy "exclusive" patterns. You can usually find some in Marshall's or Ross for a really good steal!
Yes, they are sold in many department stores. I have purchased my bags at Macy's and Bloomies in the past. I have also seen this brand at Kohl's and Lord & Taylor. You can also find LeSportsac at any luggage store.