Hello, well done you have lost weight through exercise with your lovely dogs. I bet you feel great, younger: I know I did.
Running is wonderful, but please be careful, it can be hard on the knees. You have a history of knee pain. Please, please, please see your doctor, ask if this is right for you, do you need to lose more weight first, are there alternatives, what about swimming?
With regard to your shoes, I don't know the shoes but I suspect that as North Face sell walking gear, the shoes you bought will be too rigid for comfortable running and may well have caused some of your pains. I would never wear my expensive (£70) running shoes for anything else, they are sacred... because they protect me from pain. Look for cushioned running shoes, or if you want expert advise and can pay a premium and visit a running shop. Not JJB or JD, look for the independents. Otherwise most marathon runners wear asics.
KK