I had a 3rd degree, too. It's rough.
Kegels alone aren't particularly effective if the muscles can't fully engage. When there is weakness/scar tissue present, they are hampered in their movement, and you can't really strengthen them properly. Hands on, internal pelvic physical therapy is VERY helpful. There is work you can do on your own, as well. I was treated by Tami Kent, here in Portland, who has recently published a fantastic book, called Wild Feminine, about how to self-heal. I highly recommend looking into her book, and finding a practitioner in your area who can help you.
Co-sleeping, Breastfeeding, EC'ing, Baby-wearing, Homebirthing mama to two fabulous girls 6/2007 and 8/2010