If you have a springform pan, that works really well!
I worked at an ice cream parlor in high school, and we used oreo cookies and milk to make our crusts. In a mixer, you place rushed oreos and milk and blend together until they form a soild paste (I forget the actual measurements, sorry! I know it wasn't a lot of milk, I'm sure you could google a recipe). Spread that on a cardboard circle for the bottom of the springform pan (or I guess you could grease the bottom round of the pan), add softened ice cream and fillers (like crused candies, cookies as a middle layer between ice creams) and freeze at least overnight.
We also used crushed graham crackers and butter as a crust. Same method, you want it to be a very solid consistency.
The key is to freeze the cake for as long as possible so it sets up well. Good luck!
My mom has also used a recipe from Kraft where she made an ice cream cake out of ice cream sandwiches, it was very good!!