Running to slim and tone legs?

Question
Hi,
Over the past year I have lost approx 70 lbs through eating better and walking 5 days a week.  However, I feel like my legs still could be slimmer and more toned.  I am not a runner, but currently can jog about 20 min on my treadmill.  I read somewhere that basically the only way to slim and tone your legs is through running.  If I started running more would I see a significant difference in my legs.  Would 20 min on the treadmill a few times a week combined with walking 5 days a week be enough to see a change in my legs, especially by summer?  
Thanks
Jen

Answer
Hi Jen
You will see significant difference over time,but to give you a time frame is not possible since everybody progresses at different rates.If you run more it would accelerate your situation.What i would recommend is to gradually work your way up so your able run for 45 minutes 5 times a week regardless of how slow you go.I would also use your incline on the treadmill and very the incline often to increase the work load.Just have a great deal of patience and you will see some nice results in time.I would just stick to the running and skip the walking.You can always use a walk jog combination until your capable of run the entire time.Any other questions just get in touch Jen.

All the best

John