How strong are Jessica and Luke?

Is Jessica Cap level strong or stronger? Is Luke Hulk level impervious?

Nope.

As far as the Netflix show goes, there's enough information to confirm that Jessica has these powers:

Superhuman Strength: Jessica has strength beyond that of a regular human, especially notable regarding her size. She was able to completely crush an alarm clock with a single hand when she tried to sleep off a hangover, lift a slow moving car and hit a man with enough strength to make him fly across the street.

Enhanced Speed: Jessica's overall strength allows her to run at speeds superior to the average human. She was able to catch up to a car fairly easily, and stated she can run a mile in under four minutes.

Enhanced Durability: Jessica has durability far beyond that of a regular human, being able to resist multiple beatings with little to no visible injuries. However, she is still vulnerable to gunshots and explosions.

Regenerative Healing Factor: Her augmented metabolism heals faster than an ordinary human being. She is capable of completely healing minor scratches and injuries in mere hours, and major injuries like broken ribs in just a single day. It may also allow her to not be affected by the harmful and long term affects of alcohol, leaving her only to experience intoxication and hangover while not experiencing any signs of toxicity.

Flight: Jessica is able to fly, though she has never mastered this ability. She can propel herself off a surface and through the air at various speeds and altitudes, but she sometimes gets injured while landing. Jones refers to this as "guided falling."

Moving on to Luke:

Superhuman Strength: During a fight in his bar where different opponents attacked him, Cage effortlessly tosses them from him and overpowers them. He is able to punch through solid walls and dent the auto body of motor vehicles with these punches. He is able to match Jessica Jones in strength, and push her back during a fight.

Superhuman Durability: Cage has extremely durable skin. He demonstrated it to Jones using a circular saw against his own stomach, and he survived both being stabbed in the neck and being shot with a shotgun. A doctor's drill began to smoke when drilling against his skin. Cage's skin is also fire resistant as demonstrated by him being able to withstand a point blank explosion and not feel a thing when Cage emerged from a building on fire. Nevertheless, Cage is susceptible to internal injuries and treating such injuries are complicated by the fact that Cage's extremely durable skin makes invasive surgery practically impossible. Cage could be at risk of dying from untreated internal fatal conditions, such as hydrocephalus.