Just do it, as the Nike ads say. If you haven’t done usability testing, your site is nowhere near as good as it can be. Keep the testing as simple as possible, so you actually do it. Testing with three users will expose more serious problems than you can fix in a month. And *don’t* put off fixing serious problems just because they’re going to be fixed in your planned redesign. Tweak them right now. (There’s always a tweak that can mitigate a serious problem, even if it doesn’t fix it perfectly.)