Several things have helped my ROM.
First, for extensioin, I place my heel on a chair that is sitting in front of my chair. While watching t.v., I gradually push the chair out and let the leg naturally extend. I have full extension.
Second, get in a hot bath and soak the leg in hot water. Place your foot at the bottom near the drain and gradually slide down. Very important to ice afterwards.
Third and probably most important. The bike. I've always hated the bike. The seat going up my rear etc. I've favored the eleptical trainer. Can't use that yet.
Start with the seat very high and work on extension. When your foot is at the bottom of the arc, pull back with your hamstring. I lower the seat one setting every five minutes. I just started adding resistance today. I have seen a world of difference. In fact, nut that I am, I just got back from my second 25 minute session for today.
Ice, Ice, Ice...On 20mins off 20 mins.. I set a watch alarm to keep up with it.
I'll probably give it a rest tomorrow and just walk around one of our larger malls.
Hang in there and good luck with it. Just remember that when it really hurts, it's really working.