If you want in, it makes sense to build a strong foundation. Simply put, your grades are that foundation. Check out the median GPA of students entering Ph.D. programs in clinical psychology. Most are above 3.5. Remember, research experience is important.
Clinical experience is important.
Your personal statement is important. Letters of recommendation are important. However, if your GPA doesn't meet the minimum requirements for the programs you're interested in, you won't stand much of a chance, regardless of all that other stuff. If you want to make the grade, start studying. Don't settle for a B, if you know that with a little more work you can get an A. You can always find ways to get more research or clinical experience, but the GPA you graduate with is the one you're stuck with forever.