Dreamygal, I am uncomfortable giving technical exercises over the net because of the potential for misunderstanding and hence, injury. So please be careful with this and if it starts to feel uncomfortable in your wrists, stop until you can have someone show you.
I was taught this and it helps with finger strength and independence. Place the hands at the keyboard with the wrists in a comfortable position. RAISE ALL YOUR FINGERS HIGH but curled. It should look like you are about to claw someone or something. Make sure to keep your wrists supple and elbows loose. You definately want to keep an alertness to tension. With the fingers in this position, THROW the index finger onto a key but LEAVE ALL THE OTHERS UP. You can visualize really throwing the tip of the finger into the key, like a baseball. You can throw using your whole arm as your fingers get stronger. Now, THROW the middle finger down and raise the index finger at the same time. KEEP ALL THE OTHER FINGERS UP. Keep it clean. Continue: throw the ring finger and raise the third. Repeat with the pinky, raising the fourth.
This is one way to practice the Hanon exercises. My teacher calls it practicing with raised fingers.
Perhaps this will help to establish more independence of your 4th and 5th fingers. Hope it helps.
"Hunger for growth will come to you in the form of a problem." -- unknown