Not sure about Katie Holmes' bag but I'm pretty sure you can find similar ones if there's a Sanrio boutique around where you live. Some places it's called the "Sanrio Gift Gate". They have the cutest bags! Good luck!
That particular HK line/collection has been out for a while now. If it is still selling, it will be at an outlet or one of those Japanese specialty toy stores. Most Sanrio stores will have sold out of that by now. I would say it is at least 3 years old.