Quadriceps strengthening exercises- Quad Clenches: Lie flat on your back or sit upright on a chair with leg kept horizontally on another surface. Now, tighten the muscle on the front of the thigh by pushing your knee down. You should feel your thigh muscles clench, Hold for 3 secs. Repeat 10 times twice a day. Short Arcs: Lie flat on your back or sit upright with your leg placed horizontally on a flat surface like a chair or bed. Place a rolled up towel under the knee. Pull your toes towards you and clench you thigh muscles. Slowly lift your foot up off the bed until your knee is straight (keep your knee resting on the towel). Hold for 3 secs and slowly lower them on the chair. Repeat 10 times twice a day. Straight Leg Raise: Lie flat on your back. One leg and knee will be straight and other leg should be bent. Pull your toes towards you and tighten/clench the muscle on the front of the thigh, locking your knee straight. Lift your foot up in the air, about 6 inches off the bed. Hold for 3 secs and slowly lower the leg. The knee must remain straight the whole time you are doing this exercise. Chiropractic physiotherapy.

Do gradually  it will give you strength with in a month for more progress keep continuous

you can further progress doing strait leg raise, adductor muscle squeeze. Further you can progress by doing close kinematic exercises such as mini squat, lunges in various directions. step ups, step down. u can do certain functiinal activities as an exercise such as standing up from a chair and sit down. etc do all these exs intially for 10 repititions x 2 times per day. progress by doing 15 reps and also increase the sets

2 months

Only static strengthening exercises may not help .you have to do progressive resistance exercise for strengthening.. It will take 6-8 weeks..

It's depending upon your muscles power andendure. It may take 2 months. Thank you

Increase resistance progressively to improve strengthening according to the power of muscle. It may take around 2 months approximately