There's a lot of threads where iTunes Radio data usage is reported and discussed. The first one I grabbed states around 38 MB per hour. Doing the math, 10 hours per day is 380 MB and two weeks of that is around 5 GB. Nothing in life is free.
I'm not clear on if the OP had a data usage estimate on iOS 7 without iTunes Radio. Comparing data usage of a beta against a released iOS version is apples (ha) and oranges.