Can you perform a correct Full (Rock Bottom) Squat? With both of your heels firmly on the floor through out the movement; especially as you rise up? Can you hold the bottom position for more than 20-seconds without leaning too far forward and/or coming up on the balls/toes of your feet? If not practice this first.
Wall Squats… both dynamic (full movement) all the way up and down as well as the Iso-Extreme Support (Wall) Squat (static isometric holds) holding the parallel position with good form for time. Once you feel strong on the double leg try the single leg variation… not easy at all!!!
Heel drive is the key here; you are not trying to stand up in so much as you are trying to push down driving your heels into the floor.
Use stairs (typically, starting with the second stair from the bottom), box, or a low stool to assist in the movement… that is until you can grunt your way out of the hole on your own… as in from the rock bottom position. If you are still a little bit shacky use a doorway to hold onto.
Believe it or not a counter weight may help you… hold a 10, 25, or even 35-pound dumbbell or plate out in front of you using both hands; keep the arms straight.