I'm not sure I'm convinced about using a K&N filter. While they might save you money on filter replacements, they can also lead to more engine wear in the long run. If your regular filter is getting dirty that quickly, it's a sign that something else might be wrong, and a K&N filter won't solve the underlying issue.
I'd recommend sticking with the manufacturer's recommended filter and getting your engine checked out to see if there's any problem.