K.
I'm not a medical doctor, but I do research in orthopaedic biomechanics. Your meniscus is really poorly vascularlized, which is why it heals badly/slowly. Sometimes they'll try and stitch it back together, but lots of times they'll just take the meniscus out. This seems to be pretty effective (from the literature) in reducing pain at 3 years follow-up, but can eventually lead to arthritis due to the change in contact stress on the cartilage. And, if you're overweight then this will definitely exacerbate things. Larger women tend to get arthritis in their knee because of chronic overloading of the cartilage.
If it were me I would see a physical therapist and work VERY HARD at doing what they suggest. This will probably involve some strengthening, stretching, low impact exercise (I suggest swimming), and weight loss. Bicycling may be good too - I don't know how much it's hurting you right now. Give it several months to heal. If it gets really bad to the point where it's keeping you from doing your activities of daily living you can get the cortisone shot and, eventually, the surgery. For what it's worth, I would make sure that the surgeon who does your knee (when the time comes) is someone who does a LOT of knees - like over 100 per year. Practice makes perfect with this type of thing.