Let me share with you one of the websites I follow.
Bodybuilding
In this case I shared a post about Muscle toning because is the first approach we all think inmediatly when we read your case. It's easy to end up suggesting to you to do aerobic workouts, low weight and many reps. But It's not allways that simple.
Body is not just a bunch of muscles. Everything matters. The point is to find out a balanced diet / workout routine.
To do thousand times the very same workouts for ages wont end up as expected.
In bottom lines:
Trainning goes through different statges. The first one use to be Cut Trainning. Oriented to cutdow our weight. Fatburn routine plus hypocaloric diets.
Next stage use to be a strengh trainning. In order to achive a toned shape, both woman and man should not be afraid to lift weight. Intensity here matters, so don't be afraid to lift weight (enough to make you feel unconfortable but still doable). Many reps. 10-12, 12-15 depends the muscle group we are exercising.
Goal here is to gain muscle.
Circuits are just great at this stage. Working intensely mltiple muscle groups.
Any aerobic activity should be moderated. Low-mid intensity. Otherwise we may end up burning muscle.
Here diet changes too. It's hypercaloric. To gain muscle demans calories.
I would like to be able to say all the workouts you should to do, but there's not a universal routine or plan valid for everyone :-).
Now that you are familiar with the 2 stages that matters (in your case), see a personal trainner or trainner at gym.
Ask for a customized plan. Don't miss any muscle ;-) From shoulders to toes, going through shoulders, chest, arms, abs, back, low back, buttocks, legs...
In 6-8 weeks review your plan and change it. It's important to change it over time.
Don't be shy!!! Google any doubt and ask your trainner. She/he is probably the best one you can ask to.
:-)
Hope it helps.
It may seems hard or too complexe but it's not. Just don't give up!