You need to see a spine surgeon for evaluation and diagnosis of what is going on with your spine.
You need a new MRI done because the one you have from a year ago is far to old to diagnose you with. Many, many changes can occur in a years time from when you had the last one done.
You have nerve compression going on in you spine and that is causing the numbness in your leg.
Depending on what else may or may not be going on with your spine, you may be able to heal the disc with physical therapy or other conservative treatments.
BUT, it all depends on what is going on with your spine.
Physical therapy is very different from just some kind of exercises. If you just try to do some exercises without knowing the correct ones and how to do them correctly and strengthen your cores, you could do further damage to you spine.
Get to a spine surgeon, either an orthopedic surgeon that specializes in spines or a neurosurgeon that specializes in spines only for evaluation, diagnosis and treatment plan.
Good luck
Fran